Controller Boosts Single-Ended Flyback Designs

Linear Technology’s LTC3873 is a current-mode, PWM controller that reduces the size and complexity of flyback, boost and single-ended primary-inductance converter (SEPIC) power supplies. The device contains the features necessary to design high-efficiency single-ended isolated and nonisolated flybacks rated to 25 W.

The controller is suited for applications where the input can vary from 9 V to 75 V during start-up. It will sustain operation from 4 V to 75 V after start-up. The operating frequency is fixed at 200 kHz, and standby quiescent current is 300 μA. The use of a current-sense resistor is optional

The LTC3873 is offered in 8-lead 2-mm x 3-mm DFN and 8-lead TSOT-23 packages. The LTC3873-5 version of the part has a 3.9-V UVLO, which allows converters to operate and start from a 5-V input source up to 75 V. Pricing is $1.25 for 1000 pieces.