DESCRIPTION

The LTC®3548 is a dual, constant-frequency, synchronous step down DC/DC converter. Intended for low power ap- plications, it operates from 2.5V to 5.5V input voltage range and has a constant 2.25MHz switching frequency, allowing the use of tiny, low cost capacitors and inductors with a profile ≤1mm. Each output voltage is adjustable from 0.6V to 5V. Internal synchronous 0.35Ω, 0.7A/1.2A power switches provide high efficiency without the need for external Schottky diodes.

A user selectable mode input is provided to allow the user to trade-off noise ripple for low power efficiency. Burst Mode operation provides high efficiency at light loads, while pulse-skipping mode provides low noise ripple at light loads.

To further maximize battery runtime, the P-channel MOSFETs are turned on continuously in dropout (100% duty cycle), and both channels draw a total quiescent cur- rent of only 40μA. In shutdown, the device draws <1μA.