CAT3644 is a high efficiency Quad-ModeTM fractional charge pump that can drive up to four LEDs programmable by a one wire digital interface. The inclusion of a 1.33x fractional charge pump mode increases device efficiency by up to 10% over tradi– tional 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/DIM logic input functions as a chip enable and a digital dimming interface for
The CAT3644 is a 4‑channel ultra‑high‑efficiency Quad‑Mode™ LED driver that can drive up to four LEDs at 25 mA each. It features a 1‑wire EZDim™ digital dimming interface, low‑noise input ripple, soft‑start, short‑circuit and thermal‑shutdown protection, and a “zero” current shutdown mode. The device is offered in a compact 3 mm × 3 mm 16‑pad TQFN package.
Typical applications include LCD backlights, cellular phones, digital still cameras, and other handheld devices. The datasheet provides absolute maximum ratings, recommended operating conditions, pin descriptions, timing diagrams, and extensive performance graphs covering efficiency, quiescent current, and output characteristics over voltage and temperature ranges.
| Input voltage range | 2.5 V to 5.5 V |
|---|---|
| LED forward voltage range | 1.3 V to 4.3 V |
| Power efficiency | up to 92 % |
| Package | 3 mm × 3 mm 16‑pad TQFN |
| Quiescent current (1× mode) | 1.0 mA |
| Quiescent current (2× mode) | 2.4 mA |
| EN/DIM logic high level | 1.3 V |
| EN/DIM logic low level | 0.4 V |
| Thermal shutdown temperature | 150 °C |
| Internal pull‑down resistor (EN/DIM) | 100 kΩ |
The device operates from 2.5 V up to 5.5 V.
It can drive up to four LEDs, each at up to 25 mA.
Logic high is 1.3 V and logic low is 0.4 V.
The part is offered in a 3 mm × 3 mm 16‑pad TQFN package.