200 kHz push-pull controller for isolated supplies
The MIC3809YMM is a current-mode PWM controller from Microchip designed for step-up/step-down topologies including full-bridge, half-bridge, and push-pull. It switches at 200 kHz and delivers a single transistor-driver output with a maximum duty cycle of 49%. The 49% duty ceiling is deliberate for push-pull and half-bridge designs — it prevents flux walking in the transformer by keeping the on-time below 50% per phase.
The controller operates from a 4.1 V to 14 V supply, covering the bias rail range common in telecom bricks and industrial DC-DC converters. No synchronous rectifier drive is included — the MIC3809YMM relies on an external rectifier stage, which is typical for medium-power isolated converters where the designer selects the output-side rectifier independently.
Housed in an 8-MSOP package (3.00 mm width, 0.118" body), the MIC3809YMM is a surface-mount controller that fits compact board layouts. The 8-lead MSOP footprint is shared with several Microchip PWM controllers, easing second-source qualification.