The LTC3633A-2 is a high efficiency, dual-channel monolithic synchronous buck regulator using a controlled on-time, current mode architecture, with phase lockable switching frequency. The two channels can run 180° out of phase to relax the requirements for input and output capacitance. The operating supply voltage range is from 3.6V to 20V, making it suitable for lithium-ion battery stacks as well as point of load power supply applications from a 12V or 5V supply.The operating frequency is programmable from 500kHz to 4MHz with an external resistor and may be synchronized to an external clock signal. The high frequency capability allows the use of small surface mount inductors and capacitors. The unique constant frequency/controlled on-time architecture is ideal for high step-down ratio applications that operate at high frequency while demanding fast transient response. An internal phase locked loop servos the on-time of the internal one-shot timer to match the frequency of the internal clock or an applied external clock.The LTC3633A-2 can select between forced continuous mode and high efficiency Burst Mode operation. The LTC3633A-2 and LTC3633A-3 differ in their output voltage sense range (refer to Table 1 in the Operation section of the datasheet for a description of the entire LTC3633A product family).Part NumberOutput Voltage Sense RangeSVin InputV2P5 OutputLTC3633 Pin CompatibleLTC3633A0.6V TO 6VNoYesYesLTC3633A-11.5V TO 12VNoYesYesLTC3633A-20.6V TO 6VYesNoNoLTC3633A-31.5V TO 12VYesNoNoApplicationsDistributed Power SystemsBattery Powered InstrumentsPoint of Load Power Supplies