Features

• High Voltage Operation: Up to 100V
• Large 1Ω Gate Drivers
• No Current Sense Resistor Required
• Step-Up or Step-Down DC/DC Converter
• Dual N-Channel MOSFET Synchronous Drive
• Excellent Line and Load Transient Response
• Programmable Constant Frequency: 100kHz to 600kHz
• ±1% Reference Accuracy
• Synchronizable up to 600kHz
• Selectable Pulse Skip Mode Operation
• Low Shutdown Current: 50µA Typ
• Programmable Current Limit
• Undervoltage Lockout
• Programmable Soft-Start
• 16-Pin Narrow SSOP and 28-Pin SSOP Packages

Typical Application

Description

The LTC3703 is a synchronous step-down switching regulator controller that can directly step-down voltages from up to 100V, making it ideal for telecom and automotive applications. The LTC3703 drives external N-channel MOSFETs using a constant frequency (up to 600kHz), voltage mode architecture.

A precise internal reference provides 1% DC accuracy. A high bandwidth error amplifier and patented line feed forward compensation provide very fast line and load transient response. Strong 1Ω gate drivers allow the LTC3703 to drive multiple MOSFETs for higher current applications. The operating frequency is user programmable from 100kHz to 600kHz and can also be synchronized to an external clock for noise-sensitive applications. Current limit is programmable with an external resistor and utilizes the voltage drop across the synchronous MOSFET to eliminate the need for a current sense resistor. For applications requiring up to 60V operation with logiclevel MOSFETS, refer to the LTC3703-5 data sheet.