DESCRIPTION
The LT®1737 is a monolithic switching regulator controller specifically designed for the isolated flyback topology. It drives the gate of an external MOSFET and is generally powered from a DC supply voltage. Output voltage feedback information may be supplied by a variety of methods including a third transformer winding, the primary winding or even direct DC feedback (see Applications Information). Its gate drive capability, coupled with a suitable external MOSFET and other power path components, can deliver load power up to tens of Watts.

FEATURES
■ Drives External Power MOSFET
■ Supply Voltage Range: 4.5V to 20V
■ Flyback Voltage Limited Only by External Components
■ Senses Output Voltage Directly from Primary Side Winding—No Optoisolator Required
■ Switching Frequency from 50kHz to 250kHz with External Capacitor
■ Moderate Accuracy Regulation Without User Trims
■ Regulation Maintained Well into Discontinuous Mode
■ External ISENSE Resistor
■ Optional Load Compensation
■ Optional Undervoltage Lockout
■ Shutdown Feature Reduces IQ to 50µA Typ
■ Available in 16-Pin GN and SO Packages

APPLICATIONS
■ Isolated Flyback Switching Regulators
■ Medical Instruments
■ Instrumentation Power Supplies