DESCRIPTION

The LTC®1778 is a synchronous step-down switching regulator controller optimized for CPU power. The controller uses a valley current control architecture to deliver very low duty cycles with excellent transient response without requiring a sense resistor. Operating frequency is selected by an external resistor and is compensated for variations in VIN.

FEATURES

■ No Sense Resistor Required
■ True Current Mode Control
■ Optimized for High Step-Down Ratios
■ tON(MIN) ≤ 100ns
■ Extremely Fast Transient Response
■ Stable with Ceramic COUT
■ Dual N-Channel MOSFET Synchronous Drive
■ Power Good Output Voltage Monitor (LTC1778)
■ Adjustable On-Time (LTC1778-1)
■ Wide VIN Range: 4V to 36V
■ ±1% 0.8V Voltage Reference
■ Adjustable Current Limit
■ Adjustable Switching Frequency
■ Programmable Soft-Start
■ Output Overvoltage Protection
■ Optional Short-Circuit Shutdown Timer
■ Micropower Shutdown: IQ < 30µA
■ Available in a 16-Pin Narrow SSOP Package

APPLICATIONS

■ Notebook and Palmtop Computers
■ Distributed Power Systems