TheLTC3623 is a high efficiency, monolithic synchronous buck regulator in which the output voltage is programmed with a single external resistor. The accurate internally generated 50µA current source on the ISET pin allows the user to program an output voltage from 0V to 0.5V below VIN. The user can also directly drive the ISET pin with an external voltage supply to program the converter’s VOUT. The VOUTvoltage is fed directly back to the error amplifier to be regulated to the ISET voltage. The operating supply voltage range for the SVINpin is from 15V down to 4V, while the PVINpin’s voltage range is 15V down to 1.5V, making it suitable for dual Li-Ion batteries and for taking power from a 12V or 5V rail.The operating frequency is programmable from 400KHz to 4MHz with an external RTresistor. Higher switching frequency allows the use of smaller surface mount inductors while lower frequency allows for higher power efficiency. The unique constant-frequency/controlled on-time architecture is ideal for high step-down ratio applications that are operating at high frequency while demanding fast transient response.ApplicationsTracking Supply or DDR Memory SupplyASIC Substrate BiasingPoint-of-Load (POL) Power SupplyPortable Instruments, Battery-Powered EquipmentThermo Electric Cooler (TEC) Systems