Sepic controller for non-isolated power stages
The MCP1631V-E/ML is a step-up/step-down controller IC built around the Sepic topology — it regulates an output voltage that can be above, below, or equal to the input, without a transformer. The single-output, positive-configuration transistor driver targets non-isolated DC-DC converters where a wide input range and a single inductor pair keep the BOM lean. The -40°C to 125°C junction temperature rating covers under-hood and factory-floor ambient extremes without derating.
Housed in a 20-VFQFN exposed-pad package (supplier device package 20-QFN, 4x4 mm), the part mounts on a standard surface-mount footprint. Shipping in tube format; no reel or tape options are listed for this order code, so plan for manual or tube-fed pick-and-place handling.
Control features for loop tuning
The controller includes Enable, Frequency Control, and Ramp adjustment pins — these let the designer set the switching frequency, soft-start profile, and compensation ramp without external op-amps. No clock sync input is provided, so the switching frequency is free-running and may beat against an external clock if one is present in the system. Synchronous rectification is not built in — the external transistor driver switches a single N-channel MOSFET on the primary side; the rectifier diode is external. This keeps the controller-side pin count low but places the Schottky selection in the BOM engineer's hands.