Boost DC-DC Converter IC drives white LEDs in series.
Press Release Summary:
Non-inverting Model A8430 provides programmable constant current output at up to 36 V, which is set with external resistor, and can be varied with PWM signal or control voltage at top of sense resistor when dimming control is required. With input voltage of 2.5-10 V, unit drives up to 5 LEDs at 20 mA from 3.0 V supply. Switching frequency of 1.2 MHz allows use of small external components. Model A8430 comes in 3 x 3 mm, 5-lead QFN package measuring 0.75 mm high.
Original Press Release:
High-Efficiency Boost Converter IC in Ultra-Thin Package Optimized to Drive White LEDs
A8430 is targeted at portable electronics applications
Worcester, MA - Sept. 30, 2004 - Allegro MicroSystems, Inc. has developed a high-frequency boost converter 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. 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. 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 A8430 comes in an ultra-thin 3x3 mm 5-lead QFN package 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.
Other features of the A8430 include:
o 2.5 V to 10 V input voltage
o Drives up to 4 LEDs at 20 mA from a 2.5 V supply
o Drives up to 5 LEDs at 20 mA from a 3.0 V supply
o 1.2 MHz switching frequency allows use of small external components
o 300 mA internal switch current limit
o LED brightness control
o 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 is priced at $0.47/unit for quantities of 10,000.
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. It maintains a leadership position in the integrated magnetic sensor and integrated motor driver product segments. With over 2,000 employees, Allegro is headquartered in Worcester, MA. Further information about Allegro, as well as free samples of our products, can be found at www.allegromicro.com.
