The LT1737 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. The LT1737 has a number of features not found on other isolated flyback controller ICs. By utilizing current mode switching techniques, it provides excellent AC and DC line regulation. Its unique control circuitry can maintain regulation well into discontinuous mode in most applications. Optional load compensation circuitry allows for improved load regulation. An optional undervoltage lockout pin halts operation when the application input voltage is too low. An optional external capacitor implements a soft-start function.
The LT1737 is a monolithic switching regulator controller designed for isolated flyback topologies. It drives the gate of an external MOSFET, operates from a 4.5 V to 20 V supply, and can deliver load power up to tens of watts. The device includes optional features such as load compensation, undervoltage lockout, and soft‑start.
The document details electrical characteristics, pin descriptions, typical performance curves, and package dimensions for both GN (SSOP) and S (SSOP) variants. It also offers application notes for isolated and non‑isolated designs, including recommended component values and timing considerations.
| Supply Voltage Range | 4.5 V to 20 V |
|---|---|
| Switching Frequency | 50 kHz to 250 kHz |
| Shutdown Current | 50 µA to 150 µA |
| Gate Drive Current | 100 mA |
| Minimum Input Voltage | 4.1 V (typical) to 4.5 V (minimum) |
The LT1737 operates from a supply voltage of 4.5 V to 20 V.
The shutdown current is typically between 50 µA and 150 µA.
The device can be configured for a switching frequency from 50 kHz up to 250 kHz.
The LT1737 can source up to 100 mA of gate drive current.