The LTC3555/LTC3555‑X family integrates a high‑efficiency PowerPath manager, a full‑featured Li‑ion/polymer battery charger, an ideal diode, and three synchronous step‑down switching regulators. It supports programmable USB or wall current limits (100 mA/500 mA/1 A) and provides low no‑load quiescent current in battery mode.
Typical applications include portable media players, PDAs, GPS units, handheld instrumentation, and other USB‑based handheld products. The device is offered in a 28‑lead (4 mm × 5 mm × 0.75 mm) QFN package and can be controlled via I²C or simple I/O pins.
| Input Supply Voltage | 4.35 V – 5.5 V |
|---|---|
| Switching Frequency | 1.8 MHz – 2.25 MHz |
| Peak Switch Current Limit | 2 A – 3 A |
| Low No‑Load Quiescent Current | 20 nA |
The device operates with an input supply voltage from 4.35 V to 5.5 V.
All three regulators operate at a switching frequency of 2.25 MHz (range 1.8 MHz – 2.25 MHz).