DESCRIPTION
The LTC®1435A is a synchronous step-down switching regulator controller that drives external N-channel power MOSFETs using a fixed frequency architecture. A wide duty cycle range of 5% to 99% allows high VIN to low VOUT DC/DC conversion, as well as low dropout operation that extends operating time in battery-operated systems. Burst ModeTM operation provides high efficiency at low load currents.

FEATURES
■ Dual N-Channel MOSFET Synchronous Drive
■ Programmable Fixed Frequency
■ Wide VIN Range: 3.5V to 36V Operation
■ Low Minimum On-Time (≤300ns) for High Frequency, Low Duty Cycle Applications
■ Very Low Dropout Operation: 99% Duty Cycle
■ Low Standby Current
■ Secondary Feedback Control
■ Programmable Soft Start
■ Remote Output Voltage Sense
■ Logic Controlled Micropower Shutdown: IQ < 25µA
■ Foldback Current Limiting (Optional)
■ Current Mode Operation for Excellent Line and Load Transient Response
■ Output Voltages from 1.19V to 9V
■ Available in 16-Lead Narrow SO and SSOP Packages

APPLICATIONS
■ Notebook and Palmtop Computers, PDAs
■ Cellular Telephones and Wireless Modems
■ Portable Instruments
■ Battery-Operated Devices
■ DC Power Distribution Systems