Automotive-grade 3-phase motor-control ICs with built-in commutation logic

The new A3930 and A3931 from Allegro MicroSystems Europe are automotive-grade motor controller integrated circuits with built-in commutation logic to lessen the burden on the system microprocessor, simplifying system design and reducing cost.

The new devices are ideally suited to the control of Hall-commutated 3-phase brushless DC motors driven by external N-Channel MOSFETs. If desired, the Hall sensor inputs can be driven directly by a microprocessor, which makes the A3930 and A3931 key components in a robust sensorless back-EMF solution.

The on-chip commutation logic consists of a decoder and state machine which together read the inputs of three Hall sensor inputs (or I/O signals from a microprocessor). The IC then outputs the correct gate drive signals to control six (three high-side, three low-side) external N-channel MOSFETs for driving the 3-phase motor.

The highly flexible input logic provides a wide range of control possibilities including coast, brake and pulse-width modulation functions and the facility for single-pin bi-directional control of the motor. Output pins provide status and diagnostic information on speed and direction and provide signals to enable closed-loop speed control.

Other key features incorporated on the IC are a 5 V supply for Hall sensors (used in conjunction with an external NPN transistor) and an integrated charge pump which allows operation at 100% PWM duty cycle. The driver ICs operate over a wide battery voltage range (5.5 V to 50 V) and feature extensive diagnostics and a low-current quiescent mode.

The two devices are identical apart from the addition of an optional pre-positioning function on the A3931. This operates by driving the three Hall inputs low to provide a known start-up position for the motor by forcing a position between two detent positions. This start-up condition aids any algorithms that may be used with the IC (such as sensorless back EMF commutation schemes).

The A3930 and A3931 will operate over a temperature range from -40ºC to +150ºC) and voltages from 5.5 V to 45 V, making them suitable for use in 14 V or 24 V automotive ‘under hood’ applications.

Both the A3930 and A3931 are offered in a small thermally efficient 48L eLQFP package.

LED driver IC offers high efficiency and fast switching in compact package

The new A6210 from Allegro MicroSystems Europe is an LED driver IC based on a buck (stepdown) regulator circuit using constant ‘on’ time with valley current-mode control. This control scheme allows the use of very short switch ‘on’ times, making the new device ideal for applications requiring high switching frequencies combined with high input voltages and low output voltages.

The small size and high efficiency of the A6210 makes it suitable for applications where space is limited - inside small MR16 lamps, for example - while its high current and medium-voltage capability mean that it can also be used in high-power applications such as street lighting.

System cost is reduced as a result of the high switching frequencies (up to 2.0 MHz), which allow small, low-value ancillary components such as inductors and capacitors to be used. In addition, fewer external components are required because of the high levels of integration in the device, which includes a 3-amp switch. Optimal drive circuits are used to minimise switching losses, allowing over 90% efficiency in realistic conditions.

The switching frequency is maintained constant, as the input voltage modulates the ‘on’ time. This feed-forward control ensures excellent line correction. An external resistor pulled up to the input supply programs the ‘on’ time.

The A6210 will operate over a wide input voltage range of 9 to 46 V, including 12 V nominal or maximum Class II power supplies, and produces an output voltage over the range from 0.8 to 40 V. This means that it can drive a single LED or a series string of ten or more LEDs. The output current rating of 3 A, combined with the internal switch, allow it to directly drive the new generation of very high current LEDs and LED modules. Standby current is less than 100 µA.

The A6210 is supplied in a 4-mm QFN package.

ALLEGRO MICROSYSTEMS INTRODUCES A THREE-WIRE, DYNAMIC, PEAK-DETECTING, DIFFERENTIAL HALL-EFFECT SENSOR

Simplify your Design with the Ability to Sense Numerous Targets

Worcester, MA – March XX, 2009 – Allegro MicroSystems, Inc. introduces a differential analog Hall-effect sensor that switches in response to changing magnetic fields. This new device has enhanced EMC capability that will allow users to optimize their finished sensor module by reducing their external component count, and in some cases, removing the PCB module. The combination of reduced component count, EMC enhancements, a dynamic self-calibrating algorithm, and the flexibility to sense numerous types of targets simplifies the design-in process for a wide variety of applications.

The ATS617LSG is a differential analog Hall-effect sensor that switches in response to changing magnetic fields. The device uses an analog peak-detecting algorithm, automatic gain control and an integrated tracking capacitor to provide accurate edge detection corresponding to a rotating ferrous target. The peak-detecting algorithm is ideal for use in camshaft applications with the ability to sense a wide range of target geometries including fine pitch, encoded targets.

ALLEGRO MICROSYSTEMS, INC. INTRODUCES NEW VOICE COIL MOTOR DRIVER

Designed for Camera Phone Auto Focus and Zoom Applications

Worcester, MA – March XX, 2009 – Allegro introduces a new voice coil motor (VCM) driver with I2C serial interface designed for camera lens auto focus and zoom applications. The operating voltage range for this new device is 2.3 V to 5.5 V. It has a maximum output current of 102 mA with an operating temperature range of -40°C to +85°C. This new device is targeted at both the consumer and telecommunications markets.

The output current is programmed via the I2C interface in 100 mA increments. I2C inputs set the internal 10-bit DAC output voltage reference for linear current control using an MOSFET output sink transistor and sense resistor feedback. Input supply current in sleep mode is typically less than 100nA. Logic input levels are I2C compatible and are independent of Vdd.

In most auto focus applications the lens is driven by a VCM preloaded with a spring. The lens position is proportional to current in the VCM. When the VCM current is changed the lens has a tendency to overshoot and ring at its final position. The settling

time for the ringing will add to the auto focus time thereby increasing the time between photos. In order to reduce the ringing and settling time Allegro’s A3907 offers programmable output current slew rate control. When a new current level is programmed the device steps through each possible current level between initial and final desired level. The delay between each of these levels can be programmed to automatically create either a linear ramp, two step ramp or no ramp between initial and final current. The linear ramp can be programmed with delays from 0 (no ramp) to 200 msec in 7 possible increments. The two-step ramp takes half of the current steps between initial and final current and creates delays between them of 781 nsec. In the other half of the ramp a programmable delay of between 6.25 msec and 200 msec is inserted between each of the remaining current steps.

ALLEGRO MICROSYSTEMS ANNOUNCES A NEW THREE-WIRE, TRUE ZERO-SPEED, HIGH-ACCURACY, GEAR-TOOTH SENSOR


Optimized, Magnetic Solution for Ferrous Target Applications

Worcester, MA – March XX, 2009 – Allegro MicroSystems, Inc. announces a new true zero-speed gear tooth sensor consisting of an optimized Hall IC/magnet configuration in a single over molded module. The unique integrated circuit and package design provides a user-friendly solution for digital gear-tooth sensing applications within the automotive market. This small package can be easily assembled and used in conjunction with gears of various shapes and sizes.

Allegro’s ATS667LSG incorporates a dual element Hall IC that switches in response to differential magnetic signals created by a ferrous target. The IC contains a sophisticated compensating circuit designed to eliminate the detrimental effects of magnet and system offsets. Digital processing of the analog signal provides zero speed performance independent of air gap and also dynamic adaptation of device performance to the typical operating conditions found in automotive applications (reduced vibration sensitivity). High-resolution peak detecting DACs and a bounded tracking algorithm are used to set the adaptive switching thresholds of the device. The adaptive hysteresis in

the thresholds reduces the negative effects of any anomalies in the magnetic signal associated with the targets used in many automotive applications. The advanced signal processing is ideal for transmission applications providing vibration immunity in combination with large operating air gap capability.

ALLEGRO MICROSYSTEMS, INC. INTRODUCES NEW FULL-BRIDGE MOSFET PRE-DRIVER IC

Small Profile Package with Fault Diagnostics and Reporting

Worcester, MA – March XX, 2009 – Allegro MicroSystems, Inc. has added a new full-bridge MOSFET pre-driver IC with fault diagnostics and reporting to their existing family of full-bridge controllers. Allegro’s A4940 contains a flexible input interface, bootstrap monitor circuit, wide operating voltage (5.5 to 50 V) and temperature (40°C to +150°C) ranges, in a very small profile package. It is designed for automotive applications with high-power inductive loads such as brush DC motors.

A unique charge pump regulator provides full (>10 V) gate drive for battery voltages down to 7 V and will allow the A4940 to operate with a reduced gate drive down to 5.5 V. A bootstrap capacitor is used to provide the above battery supply voltage required for N-channel MOSFETs. A unique bootstrap charge management system ensures that the bootstrap capacitor is always sufficiently charged to supply the high-side gate drive circuit.

Each of the power MOSFETs are controlled independently but are protected from shoot-through by resistor programmable dead time. Integrated diagnostics provide an indication of under voltage and over temperature faults.

ALLEGRO MICROSYSTEMS, INC. INTRODUCES A NEW PROGRAMMABLE TWO-WIRE HALL-EFFECT SENSOR

Targeted at Position Sensing Applications

Worcester, MA– March XX, 2009 - AllegroÒ introduces a new high precision, programmable two-wire Hall-effect linear sensor with a pulse width modulated (PWM) output. This is the first linear Hall-effect sensor from Allegro to include a voltage regulator, which allows the device to be powered directly from a battery. The duty cycle (DC) of the PWM output signal is proportional to an applied magnetic field. Allegro’s A1354 device converts an analog signal from its internal Hall sensor element to a digitally encoded PWM output signal. The coupled noise immunity of the digitally encoded PWM output is far superior to the noise immunity of an analog output signal. This new device is targeted at both the automotive and industrial industries.

The BiCMOS, monolithic circuit inside of the A1354 integrates a Hall element, precision temperature-compensating circuitry to reduce the intrinsic sensitivity and offset drift of the Hall element, a small-signal high-gain amplifier, proprietary dynamic offset cancellation circuits, and PWM conversion circuitry. The dynamic offset cancellation circuits reduce the residual offset voltage of the Hall element. Hall element offset is normally caused by device over molding, temperature dependencies, and thermal stress. The high frequency offset cancellation (chopping) clock allows for a greater sampling

rate, which increases the accuracy of the output signal and results in faster signal processing capability.

ALLEGRO ANNOUNCES A NEW WIDE-INPUT VOLTAGE

2 A STEP-DOWN REGULATOR

A4447 General-Purpose Buck Regulator for a Wide Variety of Applications

Worcester, MA, March xx, 2009 – Allegro expands their current family of step-down regulators by adding a 2 A fixed off-time, current-mode-controlled buck-switching regulator. This general-purpose buck regulator is targeted at the consumer electronics, office automation and industrial markets. This new device can be used in a wide variety of applications; the 8 V to 50 V input range makes it ideal where a wide range of input voltages may occur.

Allegro’s A4447 can handle a wide input of operating voltage range. The regulator requires an external clamping diode, inductor and filter capacitor, and the off time is determined by an external resistor. It will operate in both continuous and discontinuous modes. An internal blanking circuit will be used to filter out transients due to the reverse recovery of the external clamp diode. Typical blanking time is 200 nS, and the output voltage is adjustable from 0.8 V to 24 V based on a resistor divider and the 0.8 V +/- 3 percent reference.

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This new device is ideal for various end products including applications with 8 V to 50 V input voltage range needing a buck regulator for 2 A output current, consumer equipment power, uninterruptible power supplies, 12 V lighter-powered applications (portable DVD, etc.), automotive 12V or 24V input applications with higher voltage protection, printer applications, and industrial applications with 24 V or 36 V bus.

ALLEGRO MICROSYSTEMS INTRODUCES A TWO-WIRE, TRUE ZERO-SPEED, DIFFERENTIAL PEAK-DETECTING SENSOR

Magnetic Solution for Ferrous Target Applications

Worcester, MA – March XX, 2009 – Allegro MicroSystems, Inc. introduces a Hall-effect sensing integrated circuit and magnet combination that provides a user-friendly solution for true zero-speed, digital gear-tooth sensing in two-wire applications. This small package, with an optimized two-wire lead frame, can be easily assembled and used in conjunction with a wide variety of gear shapes and sizes. Allegro’s ATS682LSH is a magnetic solution for ferrous target applications.

The integrated circuit incorporates a dual-element, Hall-effect sensor and signal processing that switches in response to differential magnetic signals created by a ferrous target. The device contains sophisticated circuitry that reduces magnet and system offsets, calibrates the gain for air gap independent switch points and provides true zero-speed operation.

Signal optimization occurs at power-up through the combination of offset and gain-adjust and is maintained throughout operation with the use of a running-mode

calibration scheme. Running-mode calibration allows immunity to environmental effects such as micro-oscillations of the sensed target at start-up or sudden air gap changes. The regulated current output is configured for two-wire interface circuitry and is ideally suited for obtaining speed information in wheel speed applications. The Hall element spacing is optimized for high resolution, small diameter targets.

Allegro MicroSystems, Inc. Introduces a New MicroPower Hall‐Effect Switch with Complementary Push‐Pull Outputs

Designed to Meet the Demanding Requirements of Battery‐Operated Applications

Allegro® introduces a new ultra sensitive, Hall‐effect switch with latched digital outputs and either unipolar or omnipolar actuation. It features operation at low supply currents and voltages, making it ideal for battery‐operated electronics. Key features such as: lower minimum Vcc, a small, low‐profile package, and push‐pull complementary outputs, all serve to satisfy present and future trends in battery operated consumer products. This new device is targeted at the consumer and industrial markets.

The low operating supply voltage, 1.65 V to 3.5 V, and unique clocking algorithm assist in reducing the average operating power consumption. For example, the power requirements are less than 15 μW with a 2.75 V supply. Unlike some traditional Hall‐effect switches, Allegro’s A1171 allows the user to configure how the device is magnetically actuated. Under default conditions the device will activate output switching with either a north or south polarity magnetic field of suficient strength. In the EW, 6‐pin, microleaded package, the polarity specific actuation can be set by the user via an external selection pin to operate in a unipolar

mode, switching only on a north or south polarity field. Lastly, the A1171 has two push‐pull output structures, which source and sink current to eliminate the need for external pull‐up resistors. This polarity‐independence, as well as the minimal power requirements, allows the A1171 to easily replace reed switches, providing superior reliability and ease of manufacturing while eliminating the requirement for signal conditioning.

Allegro’s A1171 is currently available in the EW (2 mm x 1.5 mm x 0.4 mm DFN) package.

Automotive-grade Hall-effect linear current sensors offer high accuracy

The new ACS714 and ACS715 from Allegro MicroSystems Europe are a range of automotive-grade Hall-effect linear current sensors combining high accuracy with excellent voltage isolation.

The new devices are designed to provide economical and precise sensing solutions for AC and DC currents in automotive applications such as motor control, load detection and management, switched-mode power supply control, and overcurrent fault protection.

Each of the new products consists of a precise, low-offset, linear Hall sensor circuit with a copper conduction path located near the surface of the die. Applied current flowing through this copper conduction path generates a magnetic field which is sensed by the integrated Hall IC and converted into a proportional voltage. Device accuracy is optimised through the close proximity of the magnetic signal to the Hall transducer.

A precise, proportional voltage is provided by the low-offset, chopper-stabilised BiCMOS Hall IC, which is programmed for accuracy after packaging. Total output error is 1.5% at +25°C and 5% over the range -40°C to +150°C, and the risetime in response to a step input current is only 6 µs.

The internal resistance of the conductive path is typically 1.2 milliohms, which leads to low power losses. The thickness of the copper conductor allows survival of the device at up to five times overcurrent conditions.

The terminals of the conductive path are electrically isolated from the sensor leads with an isolation voltage of 2.1 kV RMS. This allows the ACS714 and ACS715 current sensors to be used in applications requiring electrical isolation without the use of opto-isolators or other costly isolation techniques.

The conductive shield across the face of the ACS714/15 is connected to ground, so that, in the presence of high dV/dt events on the device conductor, it will shunt the resultant capacitively coupled energy to ground. This prevents output voltage disturbances in the presence of very high conductor dV/dt events, which are often present in motor control and switched-mode power supply applications.

Both devices are supplied in a small, surface mount SOIC8 package. The leadframe is plated with 100% matt tin, which is compatible with standard lead (Pb) free printed circuit board assembly processes. Internally, the device is Pb-free, except for flip-chip high-temperature Pb-based solder balls, currently exempt from RoHS.

The A3908 is a low voltage bi-directional DC motor driver with a typical input voltage range of 3.0 V to 5.5 V and output currents up to 500 mA. The unique output full-bridge incorporates source side linear operation to allow a constant voltage supply across the motor coil. The A3908 is supplied in an 8-lead, 2 mm x 2 mm, lead (Pb) free DFN package and includes internal circuitry for thermal shutdown, undervoltage lockout, and crossover (shoot-through) protection. Allegro's new motor driver is targeted at the portable and instrumentation markets

Samtec will soon have available our lowest profile and smallest pitch connector system yet. Our SS4/ST4 Series is on .4mm pitch, features a blade and beam contact system, and is ideal for hand held, PDA, and other micro applications.

Features of our SS4/ST4 Series will include:

• .4mm pitch
• 4mm mated stack height
• 10 to 40 pins per row
• Dual row design
• 1mm of contact wipe
• Excellent normal force and contact deflection
• Latching option increases withdrawal force
• Optional Pick-n-Place Pads and Tape-n-Reel Packaging is available

The upcoming EFM™32 Flash microcontroller family from Energy Micro is characterized by ultra low power consumption both in active- and sleep modes. Please find below some interesting information about one of the sleep modes.

In Energy Mode 1 (EM1) the Flash memory and the ARM® Cortex™-M3 processor are disabled. This effectively reduces the energy needed for operation while peripheral functionality is maintained. Because both the Direct Peripheral Interconnect and the Direct Memory Access are available in Energy Mode 1, the system is able to collect and output peripheral data without using the CPU at all.

EFM32 MCU's autonomous profile helps embedded systems to remain in Energy Mode 1 for long periods and increases battery life time. In addition to the DMA and DPI, available peripherals include hardware 256-bit AES, External Bus Interface, integrated high frequency oscillators, ADC and DAC.

Visit the Peripheralssection to learn more about some of the EFM32 microcontrollers's low power peripherals. You can now read more about the ARM Cortex-M3, Memory Management, Debug Interface, DMA, and Clock Management.

The new EFM32 brochure is available for download in the Technologysection.

Hall-effect latch IC offers improved switching repeatability in different package options

The new A1222 from Allegro MicroSystems Europe is an extremely temperature-stable and stress-resistant Hall-effect latch IC that offers improved switching repeatability in applications such as detecting the speed and direction of ring magnets for motor commutation in the automotive, industrial and consumer market sectors.

The new device, which is available in different package styles to provide an optimum configuration for most applications, is suited for operation over extended temperature ranges up to +150°C. Superior high temperature performance is made possible through dynamic offset cancellation, reducing the residual offset voltage normally caused by device overmoulding, temperature dependencies, and thermal stress.

The A1222 includes, on a single silicon chip, a voltage regulator, Hall-voltage generator, small-signal amplifier, chopper stabilisation circuitry, a Schmitt trigger, and a short-circuit protected open-collector output that can sink up to 25 mA.

An on-board regulator permits operation with supply voltages from 3.0 to 24 V. Significant advantages are realised by reducing the minimum operating voltage. This device can be used in 3 V applications, and additional external resistance can be added in series with the supply pin for greater protection against transient events.

Two package styles provide a magnetically optimised configuration for most applications. Package type LH is a modified SOT23W surface-mount package, while the UA is a three-lead, ultra-mini-SIP for through-hole mounting. Each package type is available as lead (Pb) free (suffix, -T), with a 100% matt tin-plated lead frame.

An on-board regulator permits operation with supply voltages of 3.0 to 24 V. The advantage of reducing the minimum operating voltage is that it can be used in 3 V applications or additional

external resistance can be added in series with the supply pin for greater protection against transient events. Two package styles provide a magnetically optimized package for most applications. Package type LH is a modified SOT23W, surface mount package, while the UA is a three-lead, ultra-mini-SIP for through-hole mounting. Each package type is available as lead (Pb) free (suffix, -T), with a 100% matte tin-plated lead frame.

ASIX Launches USB 2.0 MTT Hub and USB 2.0 to Ethernet Combo Controller

ASIX Electronics Corp., a leading fabless semiconductor maker of embedded networking solutions, today announced the release of the AX88760, a USB 2.0 MTT Hub and USB 2.0 to Ethernet Combo Controller, the latest member of its High-speed USB-to-LAN controller family. With this high integration of USB to Ethernet and 3-port USB hub in a single-chip solution, the AX88760 has been designed to provide a small form factor solution that enables embedded system designers to design compact, low power, high performance yet low cost applications such as desktops, notebook PCs, Ultra-Mobile PCs, docking stations, game consoles, multifunction printers, digital-home appliances, and any embedded system that uses a standard USB port.

Recent innovations in multimedia SoCs have utilized shrinking physical form factors to reduce costs. The most efficient method of miniaturization is to reduce pin count and use a serial interface like USB, allowing the use of a USB-to-LAN solution, as opposed to a parallel local/memory bus. By combining the AX88760 with a USB host microcontroller, designers can provide Ethernet and multi-port USB connectivity for embedded systems to control remotely over a network and expand USB ports.

The AX88760’s integrated USB hub is fully compliant with USB 2.0 Specification and supports Low-Speed, Full-Speed, and High-Speed downstream devices on all of the enabled downstream ports. The AX88760 implements multiple TT (Transaction Translator) architecture that provides dedicated TT to each downstream (DS) ports, which guarantees Full-Speed (FS) data passing bandwidth when multiple FS devices perform heavy loading operations. The AX88760 integrates on-chip Fast Ethernet MAC and PHY, which is IEEE802.3 10Base-T and IEEE802.3u 100Base-TX compatible, and 24KB embedded SRAM for packet buffering to accommodate high bandwidth applications. The AX88760 has a wide array of features including support for HP Auto-MDIX, Wake-on-LAN power management, and IEEE 802.3x and backpressure flow control.

To help customers evaluate and develop applications with the AX88760, ASIX provides comprehensive technical support including hardware and software application notes, user guides, schematics, PCB layout guides, and drivers for Windows/Linux/WinCE/MacOS operating systems. In addition, ASIX has already received complete USB-IF, WHQL, and RoHS compliant certifications for the AX88760.

Ironwood Electronics is proud to offer a new contact solution for Engineering, Burn-in and Test applications. Recently released XBT product line utilizes a unique contact technology at an extremely low cost. XBT contact technology has 3 part system which includes top plunger, bottom plunger and a spring. The Brass plungers are machined, plated and assembled to a stainless steel gold plated spring inside a high temperature plastic cavity eliminating the need for an external shell or barrel. A clamshell lid with a wave spring provides the compression force on the device to make contact with XBT pins. This mechanism provides easy chip replacement and compatible with automated handler system also.

Typical specifications for the XBT contact technology include:

- Over 10GHz bandwidth @-1dB for edge pins

- Contact resistance under 50mΩ

- Self inductance under 1nH

- Capacitance under 0.3pF

- Operating temperature range -55C to +150C

- Insertion/Extraction life over 10, 000 cycles

- Current rating at 30C temperature rise is 2 Amps per pin

ASIX Electronics Corp., a leading fabless semiconductor supplier providing innovative USB-to-LAN solutions, recently announced the immediate availability of two new additions to the popular AX88x72 family for embedded Ethernet applications, the AX88772A and AX88172A, for USB-to-Ethernet and USB-to-MII bridging, respectively. The AX88x72A is the latest series in ASIX’s High-speed USB-to-LAN product portfolio. By combining the AX88x72A with a USB Host microcontroller, designers can provide Ethernet connectivity for embedded systems to distribute data and control remotely over a network.

Recent innovations in multimedia SoC’s (System-on-chip) have been based on decreasing the physical form factor to reduce costs. The most efficient method of miniaturization is to decrease the pin count and utilize the serial interfaces such as SPI and USB, allowing the use of SPI flash and USB-LAN solutions, in favor of a parallel local/memory bus. Furthermore, USB’s plug-and-play and 4-pin serial interface provides transfer speeds up to 480 Mbps, making it an ideal solution for miniature and portable handheld devices to quickly connect to networking peripherals. ASIX Electronics has released the AX88x72 series USB-to-LAN chips to satisfy the increasing market demands for adding networking capability for latest multimedia SoC’s.

The AX88x72A features a USB interface to communicate with a USB Host Controller and is compliant with USB specification V1.1 and V2.0. The AX88x72A implements 10/100Mbps Ethernet LAN function based on IEEE802.3 and IEEE802.3u standards with 24KB of embedded SRAM for packet buffering. In addition, it integrates an on-chip 10/100Mbps Ethernet PHY, simplifying system design. The AX88x72A has a wide array of features including support for HP Auto-MDIX, Wake-on-LAN power management, and IEEE 802.3x/backpressure flow control. Optional serial interfaces such as I2C, SPI, and UART are provided as a control channel from the USB Host Controller to communicate with the external MCU chip.

The AX88772A, low-pin-count (64-pin LQFP) USB 2.0 to 10/100M Fast Ethernet controller, is a high performance and highly integrated ASIC which enables a low cost, small form factor, and simple plug-and-play Fast Ethernet network connection capability for desktops, notebook PC’s, UMPC’s, cradles/port replicators/docking stations, game consoles, digital-home appliances, and any embedded system using a standard USB port.

The AX88172A, USB 2.0 to MII controller, provides an optional External Media Interface (EMI) for an external PHY or an external MAC depending on different application purposes. The EMI can be a media-independent interface (MII) for implementing 100BASE-FX Ethernet or HomePNA functions. The EMI can also be a Reverse-MII or Reverse Reduced-MII (Reverse-RMII) for glueless MAC-to-MAC connections to any MCU with Ethernet MAC MII or RMII interface. In addition, the EMI can be configured to Dual-PHY mode allowing the AX88172A to act as an Ethernet PHY or USB 2.0 PHY for external MAC devices that need Ethernet and USB interfaces in system applications. The potential and flexibility of Dual-PHY mode singles out the AX88172A as an ideal solution for growing applications such as WiMAX-to-USB modems, WiMAX ExpressCard modems, and HomePlug Powerline adapters.

To help customers evaluate and develop applications with the AX88x72A product family, ASIX provides comprehensive technical support including hardware and software application notes, user guides, schematics, PCB layout guides, and drivers for Windows/Linux/WinCE/MacOS operating systems. In addition, ASIX has already received complete USB-IF, WHQL, and RoHS compliant certifications for the AX88x72A product family.

Constant-current LED driver features 16 channels and 7-bit dot correction

New from Allegro MicroSystems Europe, the A6285 is a 16-channel constant-current LED driver featuring individual channel current adjustment via a 7-bit dot correction register.

Each channel of the A6285 can sink a constant current up to 80 mA, and a single external resistor sets the maximum LED drive current for all channels. Each channel’s drive current can be individually adjusted from 0 to 100% of the maximum value via the dot correction register, and the brightness of all the channels may be adjusted simultaneously by pulse-width modulation of the output enable (OE) input.

The A6285’s serial interface can interface directly with microprocessor or FPGA-based systems at up to 30 MHz. A serial data output permits cascading of multiple devices in applications requiring more than 16 channels.

Open LED connections can be detected and reported to the host controller through the same serial data output. The ‘fault’ output flags an LED open-circuit condition or an over-temperature (thermal shutdown) condition.

The drive outputs have active pull-ups for high-speed refresh of video and graphic displays. Staggered delays on the drive outputs during ‘on/off’ transitions help to reduce noise on the ground line.

The A6285’s CMOS logic runs on a 3.3-5 V supply. LED supply voltage can range up to 12 V, accommodating a series string of several LEDs on each channel.

Applications for the A6285 include large-scale displays and signs in the industrial, communication and office automation markets.

The device is available in a 5-mm, 32-lead QFN package with an exposed thermal pad. It is lead (Pb) free with 100% matt tin lead-frame plating.

Allegro adds a new 3 A buck converter to their existing family of general-purpose buck regulators. This new device uses valley current-mode control. This control scheme allows very low switch on times to be achieved, making it ideal for applications that require high switching frequencies combined with high input voltages (9 V - 46 V) and low output voltages (0.8 V - 15 V). Allegro's A4403 buck converter is a flexible and cost-effective solution for office automation, industrial and consumer applications.

System cost is reduced through high switching frequencies of up to 2 MHz, allowing smaller and lower value inductors and capacitors. In addition, minimal external components are required through high levels of integration. Optimal drive circuits are utilized to minimize switching losses. The switching frequency is maintained constant, as the input voltage modulates the on-time. This feed-forward control ensures excellent line correction. An external resistor pulled up to the input supply programs the on-time.

When power is initially applied and the device is enabled, a user-configurable soft-start function occurs to minimize inrush current and to prevent output overshoot. Internal housekeeping and bootstrap supplies are provided which only require the addition of one small ceramic capacitor. A top-off charge pump is also provided to ensure correct operation at light loads. Internal diagnostics provide comprehensive protection against overcurrents, input under-voltages, and over-temperature conditions.

Allegro's A4403 is supplied in a 16-contact, 4 mm × 4 mm, 0.75 mm QFN (suffix EU), with exposed pad for enhanced thermal dissipation. It is lead (Pb) free, with 100% matte tin leadframe plating.

The AX33001 is an ARM9-based single-chip Ethernet microcontroller with QoS Packet Flow Engine and Security Engine. The AX33001 features a 280MHz ARM926EJ-S CPU core, 16KB I-cache, 16KB D-cache, DDR controller and NAND/NOR flash memory interface. The hardware accelerated QoS Packet Flow Engine supports comprehensive L2-L4 QoS functions and packet forwarding engine, Network Address Translation (NAT) for IPv4/IPv6 routing and translation and advanced traffic scheduling and shaping on its WAN port. The Security Engine supports AES/DES/3DES encryption, SHA-1/MD-5 hash and Keyed-Hash Message Authentication Code. The AX33001 provides wide varieties of connectivity interfaces including 2-port 10/100Mbps Ethernet MAC with MII/RMII interface, PCI Host Bridge controller, USB 2.0 Host controller and IDE ATA-133 controller. The AX33001 is targeted at applications such as Multimedia Digital Home Gateway & Server, Secure Wireless IPv6 NAS Router among 3G Femtocell and WiMAX, ZigBee Gateway, IP-enabled POS Terminals, USB Device Server, Printer Server, Networking Attach Storage (NAS) and Multimedia Co-Processor for IP Camera, Video Conferencing and DVR.

ALLEGRO MICROSYSTEMS ANNOUNCES NEW ADDITION TO THEIR FAMILY OF CURRENT SENSORS

Next Generation, 120 kHz Bandwidth, 50-200 A Current Sensor with a 100 mW, Integrated Current Conductor for Reduced Power Loss

Worcester, MA– March XX, 2009 – Allegro MicroSystems announces a new addition to their family of current sensors. The ACS758 is a thermally enhanced, high-current, Hall-effect-based linear current sensor that provides an economical and precise solution for AC or DC current sensing. This device offers considerably higher bandwidth and reduced output noise when compared to Allegro’s older generation current sensor products. Typical applications include motor control, load detection and management, power supply and DC-to-DC converter control, inverter control, and over-current fault detection.

The device consists of a precision, low-offset linear Hall sensor circuit with a copper conduction path located near the Hall sensor die. Applied current flowing through this copper conduction path generates a magnetic field which is sensed by the integrated Hall IC and converted into a proportional voltage. Device accuracy is optimized through the close proximity of the magnetic signal to the Hall transducer, and through the integration of a high performance ferromagnetic core into Allegro’s custom CB package. A precise, proportional voltage is provided by the low-offset, chopper-stabilized BiCMOS Hall IC, which is programmed for accuracy at the factory.

The high level immunity to current conductor dV/dt signals and stray electric fields, offered by AllegroÒ proprietary integrated shield technology, guarantees low output ripple and low offset drift in high-side, high voltage applications. The internal resistance of this conductive path is 100 mW typical, providing low power loss. The terminals of the conductive path are electrically isolated from the sensor leads (pins 1 through 3). This allows the ACS758 family of sensors to be used in applications requiring electrical isolation without the use of opto-isolators or other costly isolation techniques.

Allegro MicroSystems Europe has introduced a new family of Hall-effect switches and latches which offer superior switching repeatability through their resistance to temperature variations and thermal stresses.
The new A1120, A1220 and A1221 are suited to operation over extended temperature ranges up to +150°C, and are available in two different package styles, which offer a magnetically optimised configuration for a variety of automotive, industrial and consumer applications.

The A1220 and A1221 devices are typically used to detect the speed and direction of ring magnets in motorcommutation applications, while the A1120 is most commonly used to detect the end position in automotive wiper systems and multiple discrete positions in shift selectors.

The superior high-temperature performance of the new family is made possible through dynamic offset cancellation, which reduces the residual offset voltage normally caused by device overmoulding, temperature dependencies, and thermal stress.

Each device includes, on a single silicon chip, a voltage regulator, a Hall-voltage generator, a small-signal amplifier, chopper stabilisation circuitry, a Schmitt trigger, and a short-circuit protected open-collector output that can sink up to 25 mA.

The on-board regulator permits operation with supply voltages from 3 to 24 V, although significant advantages are realised by reducing the minimum operating voltage. In particular, it allows these devices to be used in 3 V applications; alternatively, additional external resistance can be added in series with the supply pin for greater protection against transient events.

Output short-circuit protection, reverse battery protection and electrostatic discharge protection to 3 kV HBM (Human Body Model) are also incorporated.

The new products are available in two package styles. Package type LH is a modified SOT23W, surface mount package, while the UA package is a 3-lead, ultra-mini-SIP for through-hole mounting. Each package type is available in lead (Pb) free form (suffix, -T), with a 100% matt tin-plated lead frame.

New product is shipping XCalibur1331, a high-performance, conduction- or air-cooled, 6U VME solution featuring Freescale Semiconductor’s dual-core MPC8640D processor. The XCalibur1331 is ideal for ruggedized systems requiring high bandwidth processing and low power consumption. The 8640D delivers enhanced performance with AltiVec™ technology and IEEE dual-precision floating point.

XCalibur1331 features include:

· Freescale MPC 8640D processor with dual PowerPC e600 cores up to 1.25 GHz

· Two channels of up to 4 GB of DDR2-533 ECC Memory with ECC

· Up to 4 GB of NAND flash and 256 MB of NOR flash, with redundancy

· Two PrPMC/XMC slots

· Four Gigabit Ethernet ports

· Three USB 2.0 ports

· One SATA 3.0 Gb/s port

· 2eSST VME interface

· In-house X-ES operating system support includes:

o Green Hills INTEGRITY™ Board Support Package (BSP)

o Wind River VxWorks™ BSP

o QNX Neutrino™ BSP

o Linux LSP

· Guaranteed 4-hour technical response to all hardware and software questions

ASIX Electronics Corp. recently announced the availability of AX11005BF, the industry smallest single chip embedded Ethernet MCU in 8x8mm 80-pin TFBGA package, which integrates a high performance 8-bit Microcontroller with 512KB Flash memory, TCP/IP and 10/100M Fast Ethernet MAC/PHY. Being the latest member of ASIX AX110xx family, which was launched in past, the AX11005BF provides a tiny form-factor single chip solution to enable embedded system designers to design low power, high performance Embedded and Industrial Ethernet applications for the growing Embedded Networking markets with minimum board space, cost and complexity.

As the applications for remote control or remote monitoring grow, demands for adding Ethernet connectivity to an embedded system have also been increasing. The challenge for many embedded system designers today is to integrate more functionality to their products without increasing the overall size of the device. The tiny 8x8mm TFBGA package of AX11005BF is ideal for space-constrained applications and is a key benefit to designers as it allows them to reduce the overall size of their systems while utilizing all the advantages that ASIX’s System-on-Chip (SoC) technology can offer.

In addition, the TFBGA package of AX11005BF can prevent unauthorized signal pin probing or easy replacement of the device on board, which provide additional advantages for security protection for confidential data transfer on package pins or program code stored in the embedded Flash memory.

The upcoming EFM™32 Flash microcontroller family from Energy Micro is characterized by ultra low power consumption both in active- and sleep modes. Please find below some interesting information about one of the sleep modes.

In Energy Mode 2 (EM2), the EFM32 microcontrollers offer a high degree of autonomous operation while keeping the energy consumption at a very low level. The high frequency oscillator is turned off in EM2, but a 32 kHz oscillator is available for the low energy peripherals. Low power peripherals include: LCD, RTC, Low Energy TIMER, Pulse Counter, Watchdog Timer, Low Energy UART, I2C, and Analog Comparator.

Despite that the ARM Cortex-M3 CPU is not running in Energy Mode 2, the microcontroller can perform advanced operations in this sleep mode. Peripherals run autonomously due to intelligent interconnection of peripherals and memory, and the wakeup time to Active Mode, Energy Mode 0, is only a few microseconds. Low-leakage RAM ensures full data retention in EM2. Towards the launch of EFM32, Energy Micro will reveal more about the very attractive features of the new energy friendly microcontroller family. Please visit www.energymicro.com for more information about the EFM32

It is now public information that we have signed a licensing agreement with
ARM for the ARM® Cortex™-M3 core. With Energy Micro’s focus on low energy
consumption, integration, system performance and low cost, the ARM® Cortex™-M3
architecture is an ideal choice for us. The strong ecosystem of available tools,
software and knowledge within the ARM Connected Community® is also very important
for us and our customers.

We have finalized the specifications of the first product family. The specification
has been discussed and verified by customers that are market leaders in our defined
targeted applications. The entire design team is now 100% focused on designing the
world’s most energy friendly microcontrollers. The first family members will be
launched medio 2009.

Tools
Energy Micro has selected Cadence as its primary EDA tool provider, and has
licensed tools supporting a complete front-to-back design flow. The very good
tool integration and the novel support for low power designs makes Cadence the
overall best solution for Energy Micro, and it will enable us to meet our very
ambitious goals.

Extreme Engineering Solutions, Inc. (X-ES) announces the availability of seven embedded computing products based on the new Intel® Core™ i7 processor. X-ES is committed to supporting the Intel Core i7 embedded processor across Extreme Engineering’s entire line of form factors with support for the Intel Core i7-610E, i7-620LE, and i7-620UE processors. All products from X-ES based on the Intel Core i7 embedded processor are available in commercial, air-cooled to rugged, conduction-cooled versions suitable for a wide variety of commercial, industrial and military applications.

The Intel Core i7 processor represents the next step in faster, multi-core technology that dynamically maximizes performance to meet workload demands. Intel's fundamental architectural change implemented in the Intel Core i7 processor represents a significant leap forward in computational performance. By leveraging a 32-nm manufacturing process, an impressive performance-per-watt ratio is achieved. In addition, integrated DDR3 ECC dual-channel memory and high-performance graphics controllers allow the processor to break the bandwidth limitations of past system architectures. X-ES has coupled this revolutionary processor technology with the Intel® QM57 Express chipset – a low-power interface controller. This power-efficient device offers integrated PCI Express, USB, SATA 3.0 Gb/s, and graphics interfaces. The Intel Core i7 processor coupled with the Intel QM57 Express chipset provides high performance within an embedded power budget.

· XPedite7301– XMC

· XPedite7370– 3U VPX

· XCalibur4341– 6U VPX

· XCalibur4331– VME

· XPedite7330 – 3U CompactPCI

· XCalibur4301 – 6U CompactPCI

· XPedite7300 - PrPMC

"The Intel Core i7 processor represents a breakthrough in embedded performance per watt," states Ben Klam, VP of Engineering, X-ES. "Because of the processing density that can be achieved, this processor will have a significant impact on how embedded systems are designed by allowing systems to be packaged into smaller spaces or allowing more to be done within the same space.”

"It’s exciting to see Extreme Engineering harness the performance capabilities of the new Intel processors to provide such a wide variety of board form factors for the embedded computing community,” said Ryan Parker, director of marketing, Intel Embedded and Communications Division. “The new Intel Core i7 processor and Intel QM57 Express chipset deliver unprecedented computing capabilities, integration and intelligence.”

The fast fault threshold is set in the application with external resistors and the fault can be delayed by adding a capacitor to the fault pin. This delay is added for applications where the motor con­trol monitoring circuitry is far from the actual motor. The problem here is that the parasitic capacitance intrinsic in the longer cables results in an inrush spike every switching cycle. This inrush, while above the fault threshold, is not expected to latch the fault if an appropriate delay capacitor is added in the application.

The zero current reference pin can be used as a reference input to an external A/D converter. The purpose of this pin is to help the application in establishing a voltage reference. This reference often saves customers some external components and aids in system cali­bration.

By using primary-side voltage sensing, the need for a secondary-side resistive voltage divider is eliminated. This has the additional benefit of reducing leakage currents on the secondary side of the transformer. To extend battery life, they feature very low supply current draw in shutdown and standby mode.

In the A8732, the switch current limit can be programmed from 0.45 to 1.5 in 16 steps with single wire interface, through the CHARGE pin. The current limit for the A8735 is fixed at 1 A.

The IGBT driver also has internal gate resistors for minimum external component count. The charge and trigger voltage logic thresholds are set at 1 VHI (min) to support applications implementing low-voltage control logic. The devices are available in an 8-contact 2 mm x 2 mm DFN package with a 0.60 maximum overall package height.

The translator is the key to the easy implementation of the devices. Simply inputting one pulse on the STEP input drives the motor one microstep. There are no phase sequence tables, high frequency control lines, or complex interfaces to program. The interface is an ideal fit for applications where a complex microprocessor is unavailable or is overburdened.

The A4986/A4987 devices are dual DMOS full-bridge stepper motor drivers with parallel input communication and overcurrent protection. Each full-bridge output is rated up to 35 V and ±2 A. These devices include a fixed off-time pulse width modulation (PWM) current regulator, along with a 2- bit nonlinear DAC (digital-to-analog converter) that allows stepper motors to be controlled in full, half, and quarter step modes. The PWM current regulator uses the Allegro® patented mixed decay mode for reduced audible motor noise, increased step accuracy, and reduced power dissipation. Internal synchronous rectification control circuitry is provided to improve power dissipation during PWM operation. Industry standard PHASE, I0, I1 logic inputs are used to control each full-bridge so these motor drivers can easily replace most existing drivers.

The starter kit board features Energy Micro's EFM32G890F128 microcontroller, a 160 segment LCD display driven by the microcontroller's energy efficient on-chip LCD controller, and a touch slider to demonstrate the microcontroller's capacitive sensor interface capability. Other I/O facilities include 4 x LEDs, 2 x push buttons and a dedicated MCU reset button. All unused I/O is terminated at the board edge for users to access via a standard PCB header. An expansion port is also included for more complex application development.

To enable users to further optimise application energy efficiency, Energy Micro's unique Advanced Energy Monitoring system (AEM) means current consumption data can be accurately viewed in real time, allowing adverse energy drains to be identified and remedied at an early stage. To simplify application debugging and programming the on-board J-Link emulator is accessible via both USB and standard 20-pin connectors.

The starter kit is supported by Energy Micro's energyAware™software library, built around ARM's standard CMSIS abstraction layer. Third party support includes IAR's Embedded Workbench®, Keil's MDK-ARM, and CrossWorks from Rowley Associates.

Samtec has recently expanded its line of IP68-rated sealed interconnect systems with the new AccliMate™ Sealed Rectangular Ethernet Cable Plug & Receptacle. This new system, like the entire line of AccliMate™ products, is designed for industrial and other harsh environments with a silicon seal that meets IP68 specifications for dust and waterproof sealing. The rectangular design saves space compared to traditional IP68 interconnects making the system particularly well suited to smaller and lower profile applications. In addition, a unique push-to-seal positive latching system with audible click slows for easier mating and requires less space for mating connectors and cables.

AccliMate™ Rectangular Ethernet Panel Mount Sockets (RPBE Series) meet CAT5e, CAT, and CAT3 specifications and are available in either single or dual port designs. The Cable Plug (RCE Series) is available double-ended (both ends sealed) or with a blunt cut (one end sealed). The rugged 28 AWG cable, with copper conductors and PVC jacket, comes in a choice of 2, 3, or 5 meter assembled lengths. Dust caps for protection while the system is unmated are available for both cable plugs and sockets.

In addition to the Ethernet system, Samtec also offers and IP68-rated sealed rectangular Acclimate™ cable plug and receptacle featuring its rugged Tiger Eye™ contacts on.050” pitch. A power system on .100” pitch is currently in development. IP68-rated Sealed Circular AccliMate™ systems include cable plugs and receptacles with a choice of Tiger Eye™ highly reliable contacts, Ethernet, USB, Mini USB, Power, or High Density inserts. Customer sealed interconnect designs are also available.

The new A8512 from Allegro MicroSystems Europe is a multi-output white LED RGB driver IC for the LED backlighting of large-area LCD monitors and television screens.

The new device integrates a scalable-output boost controller operating in constant-frequency current mode control - adjustable between 300 kHz and 1 MHz - driving an external MOSFET. It integrates six internal current sinks each capable of sinking up to 80 mA, which can be combined together to achieve even higher currents. PWM dimming allows LED currents to be precisely controlled over a 500:1 ratio as a percentage of the maximum setpoint determined by the user.

Multiple A8512 devices can be connected in parallel, with one master controller controlling the boost stage and up to five slave controllers acting as LED sinks. This configuration allows up to 36 LED strings to be powered by a single boost converter, significantly reducing the number of external components required.

Other features include controlled start-up using enable, PWM signal or battery voltage ramp, and active current sharing between LED strings with ±0.6% accuracy and matching. There is no audible MLCC noise during PWM dimming.

The A8512 operates from a single supply of 8-24 V. It provides protection against overvoltage, open or short-circuited LED string, and overtemperature. A dual-level cycle-by-cycle current limit function provides soft start and protects against overloads.

The A8512 is available in a 28-contact 5 mm x 5 mm QFN package (ET), with an exposed thermal pad for enhanced thermal dissipation. For single-sided PCB manufacturing capability, the device is also available in a 24-pin SOICW package (LB), with internally fused pins for enhanced thermal dissipation. Both packages are lead (Pb) free, with 100% matt tin lead-frame plating.

Samtec, Inc., a worldwide leader in electronic interconnect solutions, provides unrivaled design and development services for Application Specific Products (ASPs). Whether your application requires simple modifications to a standard cataloged product or a completely custom engineered design, Samtec has the expertise, the willingness, and the ability to meet and exceed your specifications.

Design and development of ASPs is timely and cost-effective with Samtec’s in-house manufacturing, testing, and development capabilities (including stereolithography, mold design & fabrication and SMT lab), quick-turn samples and prototypes, and unmatched Signal Integrity expertise.

For applications where a standard product is close, but not exactly what is needed, Express Modifications can be quickly and economically achieved. Everything from pin and body modifications to special cables and platings is possible. Express Modifications offer short lead times, quick-turn prototype samples, and no Nonrecurring Engineering Charges (NREs), tooling charges, or Minimum Order Quantities (MOQ).

For applications where an entirely new design is required, Samtec’s Signal Integrity expertise, in-house manufacturing facilities, and can-do attitude make Engineered Custom interconnects a realistic choice. Full engineering and testing & development support, vertical integration, and connector design expertise, help take the uncertainty and complications out of the design process, whether you need special housings or metals, custom components or wiring, or unique rugged features.

ASIX Launches Low-Power USB to Ethernet Controller

ASIX Electronics Corp., a leading fabless semiconductor maker providing innovative USB-to-LAN solutions, today announced it is now delivering the AX88772B, a USB to Ethernet controller with low power and low-pin-count for the Embedded Ethernet applications. The AX88772B is the latest member being added to ASIX’s High-speed USB-to-LAN product portfolio. The AX88772B USB to Ethernet controller has been designed to provide a small form factor solution that enables embedded system designers to deliver Ethernet connectivity while leveraging the proliferation of USB 2.0 technology.

The AX88772B features a USB interface to communicate with a USB Host Controller and is compliant with USB specification V1.1 and V2.0. The AX8872B integrates on-chip Fast Ethernet MAC and PHY, which is IEEE802.3 10Base-T and IEEE802.3u 100Base-TX/ 100BASE-FX compatible. AX88772B can be used in any embedded system with a USB host microcontroller that needs a twisted pair physical connection or fiber PECL interface to external 100Base-FX optical transceiver module.

The AX88772B supports advanced low-power features including very low power Wake-on-LAN (WOL) mode and dynamic power management, to reduce power dissipation during idle or light traffic period. The AX88772B also supports AutoDetach power saving, Detach from USB host when Ethernet cable is unplugged. The AX88772B offers a wide array of features including IPv4/IPv6 checksum offload engine, HP Auto-MDIX, and IEEE 802.3x and back-pressure flow control. The AX88772B supports two operating temperature ranges, namely, commercial grade from 0 to 70 °C and industrial grade from –40 to 85 °C.

The AX88772B, low-pin-count (64-pin LQFP) USB 2.0 to 10/100M Fast Ethernet controller, is a high performance and highly integrated ASIC which enables a low cost, small form factor, and simple plug-and-play Fast Ethernet network connection capability for desktops, notebook PC’s, UMPC’s, cradles/port replicators/docking stations, game consoles, digital-home appliances, and any embedded system using a standard USB port.

To help customers evaluate and develop applications with the AX88772B product family, ASIX provides comprehensive technical support including hardware and software application notes, user guides, schematics, PCB layout guides, and drivers for Windows/Linux/WinCE/MacOS operating systems

The new A4936 from Allegro MicroSystems Europe is a three-phase brushless DC motor pre-driver IC targeted at applications within the office automation sector including laser printer and copier drum drives.

The new device incorporates outputs for the direct high-current gate drive of an all N-channel power MOSFET three-phase bridge with a maximum supply voltage of 38 V. Also included in the A4936 device are three Hall-element inputs, a sequencer for commutation control, fixed off-time pulse width modulation (PWM) current control, and locked-rotor detection.

Output current is scaled by the capability of the external MOSFETs, and locked-rotor detection delay is set by an external capacitor on the CLD terminal. The PWM, DIR, BRAKE and STOP inputs can be used to control motor speed, position, and torque. The motor speed can be determined using the motor’s FG (frequency generator) coil signal, which is amplified and shaped with the internal differential amplifier and comparator to produce a digital FG signal output.

The external MOSFETs can be pulse-width-modulated by using an external signal on the PWM input or the internal PWM current regulator. In either case, the synchronous rectification capability of the A4936 reduces power dissipation by turning on the appropriate MOSFETs during current decay.

The Hall elements can be inexpensive types, and are used in conjunction with internal noise filtering to prevent false commutation signals. The A4936 provides a regulated 7.5 V supply to power the three Hall elements. Internal circuit protection includes thermal shutdown with hysteresis, undervoltage lockout and dead-time protection. Special power-up sequencing is not required. The operating temperature range is -20°C to +105°C.

The A4936 is supplied in a 5 ´ 5 mm, 32-terminal QFN package with exposed thermal pad. This small footprint package is lead (Pb) free with 100% matt tin leadframe plating.

The Crydom CTR series offers UL-approved AC output ratings of 25A per channel at 600V AC, AC or DC input control, zero voltage or random turn on, as well as IP20 touch-safe construction with integral heat sink.

LED backlight driver IC for large displays

The new A8512 from Allegro MicroSystems Europe is a multi-output white LED RGB driver IC for the LED backlighting of large-area LCD monitors and television screens.

The new device integrates a scalable-output boost controller operating in constant-frequency current mode control – adjustable between 300 kHz and 1 MHz - driving an external MOSFET. It integrates six internal current sinks each capable of sinking up to 80 mA, which can be combined together to achieve even higher currents. PWM dimming allows LED currents to be precisely controlled over a 500:1 ratio as a percentage of the maximum setpoint determined by the user.

Multiple A8512 devices can be connected in parallel, with one master controller controlling the boost stage and up to five slave controllers acting as LED sinks. This configuration allows up to 36 LED strings to be powered by a single boost converter, significantly reducing the number of external components required.

Other features include controlled start-up using enable, PWM signal or battery voltage ramp, and active current sharing between LED strings with ±0.6% accuracy and matching. There is no audible MLCC noise during PWM dimming.

The A8512 operates from a single supply of 8-24 V. It provides protection against overvoltage, open or short-circuited LED string, and overtemperature. A dual-level cycle-by-cycle current limit function provides soft start and protects against overloads.

The A8512 is available in a 28-contact 5 mm x 5 mm QFN package (ET), with an exposed thermal pad for enhanced thermal dissipation. For single-sided PCB manufacturing capability, the device is also available in a 24-pin SOICW package (LB), with internally fused pins for enhanced thermal dissipation. Both packages are lead (Pb) free, with 100% matt tin lead-frame plating.

These extremely temperature-stable and stress-resistant sensor ICs are especially suited for applications that require high-voltage transient protection close to the sensors, but where space or distance considerations preclude the use of external protection devices. Typical uses include motor commutation in sunroofs and power windows within the automotive market.

The A1225/7/9 devices include Allegro’s advanced offset cancellation technique which, along with high-speed 4-phase chopping, gives lower noise on the output, less switch-point variation with temperature, and faster settling times. The resulting improvements in noise and switch-point drift lead to much better switching accuracy and repeatability.

Superior high-temperature performance is made possible through a Schmitt trigger circuit that maintains operate and release point symmetry by compensating for temperature changes in the Hall element. In addition, the internal compensation circuitry provides magnetic switch points that become more sensitive with temperature, hence offsetting the usual degradation of the magnetic field with temperature. The symmetry capability makes these devices ideal for use in pulse-counting applications where duty cycle is an important parameter.

The improved high-voltage transient protection allows the devices to survive the tests specified in ISO 7637-2 and a 40 V load dump for less than 0.5 s with minimal external protection. In addition, enhanced ESD (electrostatic discharge) prevention structures provide ESD protection of up to 8 kV HBM (human body model) without the need for external protection components.

The three basic devices (A1225, A1227 and A1229) are identical except for magnetic switch points. Each device includes, on a single silicon chip, a voltage regulator, Hall-voltage generator, temperature compensation circuit, signal amplifier, Schmitt trigger, and a buffered open-drain output to sink up to 25 mA. The on-board regulator permits operation with supply voltages of 3.8 V to 24 V.
The first character of the part number suffix determines the device operating temperature range, with suffix ” L” denoting -40°C to +150°C. Two package styles provide a magnetically optimised package for most applications. Suffix “LT” is a miniature SOT89/TO-243AA transistor package for surface-mount applications, while suffix “UA” is a 3-lead ultra-miniature single-inline package. Both packages are lead (Pb) free with 100% matt tin leadframe plating.