Speed control for a 3-wire or 4-wire fan
The TC649BEUA is a brushless DC (BLDC) fan speed controller from Microchip's FanSense™ series. It drives the low-side pre-driver output to regulate fan speed based on a parallel interface input, making it a straightforward fit for systems that need closed-loop fan control without a full motor driver IC. Operating from a 3V to 5.5V supply, it handles the common logic and fan supply rails found in embedded systems, telecom equipment, and industrial control panels.
Package and board-fit for hand-soldering
Housed in an 8-MSOP package (3.00 mm width, 0.118" pitch), the TC649BEUA is hand-solderable with a fine-tip iron and a steady hand — no hot-air station required. The 8-TSSOP alternative footprint is identical, so a single PCB layout covers both. Surface-mount assembly is the intended method, but the 0.65 mm lead pitch is manageable for prototype rework with flux and tweezers.
Temperature range and deployment context
The industrial temperature grade covers most fan-cooled enclosures without derating.