DESCRIPTION
The LTC®3446 combines a synchronous buck DC/DC converter with two very low dropout (VLDO) linear regulators to provide up to three stepped-down output voltages from a single input voltage. The input voltage range is ideally suited for Li-Ion battery-powered applications, as well as powering low voltage logic from 5V or 3.3V rails. The output voltage range extends down to 0.4V for the VLDO regulators and 0.8V for the buck.

FEATURES
■ High Efficiency Triple Step-Down Outputs from a
   Single Input Supply
■ 1A Synchronous Buck Regulator Provides Main
   Step-Down Output and Powers Two 300mA VLDO™
   Linear Regulators
■ Output Voltages as Low as 400mV (VLDO Outputs)
■ Power Good Output
■ Input Voltage Range: 2.7V to 5.5V
■ Independent Enable Pin for Each Supply
■ Low (140µA Typ) No-Load Quiescent Current with
   All Outputs Enabled
■ Constant Frequency Current Mode Operation
■ 2.25MHz Switching Frequency Uses Small Inductors
■ Defeatable Automatic Burst Mode® Operation for
   High Efficiency at Light Loads
■ ±1.5% Reference Accuracy
■ Overtemperature Protection
■ Thermally Enhanced 4mm × 3mm 14-Pin DFN
   Package

APPLICATIONS
■ Low Power Handheld Devices
■ Low Voltage and Multivoltage Power for Digital Logic, I/O, FPGAs, CPLDs, ASICs and CPUs