Low Voltage Current Mode PWM Controller

The LT1619 is a fixed frequency PWM controller for implementing current mode DC/DC converters with minimum external parts. The LT1619 operates with input voltages ranging from 1.9V to 18V and is suitable for a variety of battery-powered and distributed DC/DC converters. The internal rail-to-rail N-channel MOSFET driver operates either from the input in the non-bootstrapped mode or from the output in bootstrapped operation. The driver is designed to drive a low side power transistor in boost, SEPIC, flyback and other topologies.

Converter efficiency is improved at heavy loads with a 53mV current sense voltage and at light load with Burst Mode operation. The operating frequency is internally setat 300kHz. The oscillator can also be synchronized externally up to 500kHz. No load quiescent current is 140µA and shutdown current is 15µA.

The LT1619 is available in 8-lead MSOP and SO packages.

Applications

* 3.3V to 5V DC/DC Converters

* Distributed Power Supplies

* Isolated Power Supplies

* Wide VIN Range: 1.9V to 18V

* 300kHz Fixed Frequency Current Mode Control

* 1A Rail-to-Rail N-Channel MOSFET Driver

* Low 53mV Current Limit Threshold Voltage Improves Efficiency

* Implements Boost, SEPIC and Flyback Converters Requiring Low Side Power Transistors

* Internal Current Sense Amplifier with Leading Edge Blanking

* Up to 500kHz External Synchronization

* Burst Mode® Operation for High Efficiency at Light Load

* 140µA Quiescent Current

* 15µA Shutdown Current

* 8-Lead MSOP and SO Packages