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High-Performance Power ICs and Hall-Effect Sensors
High-Efficiency Boost Converter ICs in Ultra-Thin
Package —
Optimized to Drive White LEDs
A8430 and A8431 targeted at Portable Electronics Applications 
Worcester, MA — December 14, 2004 — Allegro MicroSystems, Inc. has developed a pair of high-frequency boost converters with constant current output — ideal for driving white LEDs or similar loads.
The A8430 is a non-inverting boost dc-dc converter, providing a programmable constant current output at up to 36 V for driving white LEDs in series. Driving the LEDs in series ensures identical currents and uniform brightness, and is more efficient than charge pump solutions thus leading to longer battery life. The output current is set with an external resistor, and can be varied with either a PWM signal or a control voltage at the top of the sense resistor when dimming control is required.
The A8430 comes in an ultra-thin 3x3 mm five-lead QFN package that is only 0.75 mm high, and utilizes an industry-standard pinout and equivalent SOT-23-5 footprint - an easy drop-in replacement for competitive products.
The A8431 is similar to the A8430, but adds an Overvoltage Protection feature (32 V) and is packaged in an even smaller 2x3 mm (0.75 mm high) six-lead QFN.
Other features of the A8430 and A8431 include:
- 2.5 V to 10 V input voltage
- Drives up to four LEDs at 20 mA from a 2.5 V supply
- Drives up to five LEDs at 20 mA from a 3.0 V supply
- 1.2 MHz switching frequency allows use of small external components
- 300 mA internal switch current limit
- LED brightness control
- Load current set by external feedback resistor
"Not only does our A8430 QFN-5 drop-in to the same footprint as SOT- and TSOT-23-5 packages, but it reduces the profile to just 0.75 mm nominal height," said Strategic Marketing Manager Mark Gaboriault.
The A8430 is supplied in a 3x3 mm QFN-5 package, and the A8431 is supplied in a 2x3 mm QFN-6 package.
Allegro MicroSystems, Inc. is a supplier of advanced mixed-signal power semiconductors and Hall-effect sensors targeted toward the automotive, communications, computer/office automation, consumer and industrial markets. With over 2,400 employees, Allegro is headquartered in Worcester, MA. Further information about Allegro can be found at www.allegromicro.com.
Editorial Contact:
Stephanie Fennelly
Director – Marketing Communications
Tel: (508) 854-5363
sfennelly@allegromicro.com