DESCRIPTION
The LTC®1625 is a synchronous step-down switching regulator controller that drives external N-Channel power MOSFETs using few  external components. Current mode control with MOSFET VDS sensing eliminates the need for a sense resistor and improves efficiency. The frequency of a nominal 150kHz internal oscillator can be synchronized to an external clock over a 1.5:1 frequency range.

FEATURES
■ Highest Efficiency Current Mode Controller
■ No Sense Resistor Required
■ Stable High Current Operation
■ Dual N-Channel MOSFET Synchronous Drive
■ Wide VIN Range: 3.7V to 36V
■ Wide VOUT Range: 1.19V to VIN
■ ±1% 1.19V Reference
■ Programmable Fixed Frequency with Injection Lock
■ Very Low Drop Out Operation: 99% Duty Cycle
■ Forced Continuous Mode Control Pin
■ Optional Programmable Soft Start
■ Pin Selectable Output Voltage
■ Foldback Current Limit
■ Output Overvoltage Protection
■ Logic Controlled Micropower Shutdown: IQ < 30µA
■ Available in 16-Lead Narrow SSOP and SO Packages

APPLICATIONS
■ Notebook and Palmtop Computers, PDAs
■ Cellular Telephones and Wireless Modems
■ Battery Chargers
■ Distributed Power