LTC3548IMSE#PBF

LTC3548 Dual Synchronous, 400mA/800mA, 2.25MHz Step-Down DC/DC Regulator FEATURES n n n n n n n n n n n n n n n DESCRIPTION High Efficiency: Up to 95% Very Low Quiescent Current: Only 40μA Low Output Ripple Burst Mode® Operation 2.25MHz Constant-Frequency Operation High Switch Current: 0.7A and 1.2A No Schottky Diodes Required Low RDS(ON) Internal Switches: 0.35Ω Current Mode Operation for Excellent Line and Load Transient Response Short-Circuit Protected Low Dropout Operation: 100% Duty Cycle Ultralow Shutdown Current: IQ < 1μA Output Voltages from 5V down to 0.6V Power-On Reset Output Externally Synchronizable Oscillator Small Thermally Enhanced MSOP and 3mm × 3mm DFN Packages The LTC®3548 is a dual, constant-frequency, synchronous step down DC/DC converter. Intended for low power applications, 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 current of only 40μA. In shutdown, the device draws