Charge Pump Family Adds Siblings May 2004 Issue Published Date: May 03, 2004
Two additions to the AATxxxx family of charge pumps for white LEDs, the AAT3131 and AAT3134, provide independent control for two separate banks of LEDs. The AAT3131 produces current levels up to 20 mA from three of its outputs and 30 mA from a fourth with a 2.7V to 5.5V input. It supports six outputs up to 20 mA and allows independent control in two groups of four and two. Outputs from both devices can be operated independently or in parallel. Other shared features include a 1.5X fractional charge pump and a 1X load, the company’s simple serial control (S2Cwire) interface, a 32-level logarithmic scale brightness control, and a 1 MHz switching frequency that accommodates the use of very small external capacitors. For example, two 1 µF flying capacitors and two 1µF capacitors at VIN and VOUT. They also include thermal management protection, automatic soft-start circuitry, and a low current shutdown feature. Operating temperature is from –40°C to +85°C. Prices for the AAT3131 in a 12-pin TSOPJW and AAT3134 in a 16-pin QFN are $1.95 and $2.26 each/1,000, respectively. ANALOGIC TECHNOLOGIES INC., Sunnyvale, CA. (408) 737-4600.
