The LTC3531/LTC3531-3.3/LTC3531-3 are synchronous buck-boost DC/DC converters that operate from input voltages above, below or equal to the output voltage. The topology incorporated in the ICs provides a continuous transfer through all operating modes, making the product ideal for single cell Li-Ion and multicell alkaline or nickel applications. The converters operate in Burst Mode, minimizing solution footprint and component count as well as providing high conversion efficiency over a wide range of load currents. The devices include two 0.5Ω N-channel MOSFET switches and two P-channel switches (0.5Ω, 0.8Ω). Quiescent current is typically 16μA, making the parts ideal for battery power applications. Other features include a <1μA shutdown current, current limiting, thermal shutdown and output disconnect. The parts are offered in a 6-pin ThinSOTTM package for fixed voltage versions or a 3mm × 3mm DFN package for fixed and adjustable versions.
The LTC3531 family (including LTC3531‑3.3 and LTC3531‑3) are synchronous buck‑boost converters that operate from input voltages above, below, or equal to the output voltage. They deliver up to 200 mA at 3.3 V from a 3.6 V input and feature burst‑mode operation, ultra‑low quiescent current, and built‑in protection functions such as over‑temperature and output‑disconnect.
Typical applications include handheld instruments, MP3 players, PDAs, and other battery‑powered devices. The devices are offered in 6‑pin ThinSOT and 3 mm × 3 mm DFN packages, with only three external components required for the fixed‑voltage versions.
| Input Voltage Range | 1.8 V to 5.5 V |
|---|---|
| Output Voltage (3.3 V version) No Load | 3.32 V typ |
| NMOS Switch Leakage | 0.2 pA |
The minimum startup voltage is 1.65 V (typical) with a guaranteed minimum of 1.8 V.
Only three external components are required for the fixed‑voltage versions.