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CAT3637

6-Channel Programmable High Efficiency Quad-Mode™ LED Driver

Features	Description	Applications

FEATURES

High efficiency 1.33x charge pump
Quad-Mode charge pump: 1x, 1.33x, 1.5x, 2x
Drives 6 LEDs between 30mA and 0mA each
1-wire EZDim™ interface with 2mA step
Power efficiency up to 92%
Low noise input ripple in all modes
“Zero” current shutdown mode
Soft start and current limiting
Short circuit protection
Thermal shutdown protection
Tiny 3mm x 3mm, 16-pad TQFN package

DESCRIPTION

The CAT3637 is a high efficiency Quad-Mode fractional charge pump that can drive up to six LEDs programmable by a 1-wire digital interface. The inclusion of a 1.33x fractional charge pump mode increases device efficiency by up to 10% over traditional 1.5x charge pumps with no added external capacitors.

Low noise input ripple is achieved by operating at a constant switching frequency which allows the use of small external ceramic capacitors. The multi-fractional charge pump supports a wide range of input voltages from 2.5V to 5.5V.

The EN/SET logic input functions as a chip enable and a digital programming interface for setting the current in the LED channels. The 1-wire pulse-programming interface supports 15 linear steps from zero current to 30mA full-brightness in 2mA steps.

The device is available in a tiny 16-pad TQFN 3 x 3mm package with a maximum height of 0.8mm.

Catalyst Semiconductor’s Quad-Mode 1.33x, charge pump switching architecture is patented.

TYPICAL APPLICATION

CAT3637 typical application