LTC3672B-2

LTC3672B-2 Monolithic Fixed-Output 400mA Buck Regulator with Dual 150mA LDOs in 2mm × 2mm DFN FEATURES n Triple Output Supply From a Single 2.9V to 5.5V Input n Buck DC/DC: Fixed 1.2V Output, Up to 400mA n LDO1: Fixed 2.8V Output, Up to 150mA n LDO2: Fixed 1.8V Output, Up to 150mA n ±2.5% Reference Accuracy n Constant-Frequency 2.25MHz Operation n Minimum External Component Count n Current Mode Operation for Excellent Line and Load Transient Response n Internal Soft-Start for Each Output n Single Enable Pin Turns On/Shuts Down All Three Outputs n Tiny 2mm × 2mm × 0.75mm DFN Package APPLICATIONS n DMB and DVB-H Cellphones n Handheld Products (PDA, PMP, GPS) n Multivoltage Power for Digital Logic, I/O, FPGAs, CPLDs, ASICs, CPUs, and RF Chipsets DESCRIPTION The LTC®3672B-2 is a triple power supply composed of a 400mA synchronous buck regulator and two 150mA low-dropout linear regulators (LDOs). Constant-frequency 2.25MHz operation is maintained down to very light loads. The input supply range of 2.9V to 5.5V is especially wellsuited for single-cell Lithium-Ion and Lithium-Polymer applications, and for powering low voltage ASICs from 3.3V or 5V rails. The LTC3672B-2 regulates 1.2V at the buck output, 2.8V at the LDO1 output, and 1.8V at the LDO2 output. External component count is minimal—all that is needed is a single inductor, an input capacitor, and output capacitors for each of the three outputs. Control loop compensation is internal to the LTC3672B-2. The LTC3672B-2 is ava...