SC70 Boost Converter Drives Four White LEDs

The LT1937 boost converter has been optimized to drive up to four white LEDs from a 3.2V supply and up to six LEDs from a 5V supply. Its 1.2 MHz switching frequency allows for use of small-value external components, such as a 22 µH inductor and 0.22 µF output capacitor, and minimizes both input and output noise. The device features an efficiency of 84% and less than 1 µA of shutdown current with an input voltage range of 2.5V to 5.5V. Other features include a feedback voltage of 95 mV ±9 mV that promises good brightness control, even when partially dimmed, to current levels of 6 to 8 mA. The LT1937ESC6 is available from stock in a six-lead SC70 package and is priced at $1.45 each/1,000. The LT1937ES5 is also available from stock in a five-lead thin SOT package and costs $1.30 each /1,000. LINEAR TECHNOLOGY CORP., Milpitas, CA. (800) 454-6327.