What the function ratings mean for fit
The TC655EUN is a speed controller for brushless DC (BLDC) fans — it handles the commutation logic and speed regulation, not the power stage directly. The pre-driver low-side (2) output drives two external N-channel MOSFETs that switch the fan windings. Speed and fault monitoring happen over the I²C interface — the host microcontroller reads tachometer feedback and sets the target duty cycle over a two-wire bus, saving GPIO pins on the main controller. Supply range is 3V to 5.5V from a single rail — the same rail that powers the fan's logic can feed the controller, simplifying the power tree on a fan-control PCB.
Temperature grade and package constraints
Housed in a 10-MSOP package (3.00 mm width) — the 0.50 mm pitch demands careful PCB layout for the I²C pull-up resistors and the gate-drive traces to the external MOSFETs, but the footprint is compact enough for a 2-layer board.
Compliance and documentation
ROHS3 compliant — no restricted substances above the threshold limits, no exemption expiry to track for EU or global BOMs. Supplied in tube packaging — the 10-MSOP parts ship in antistatic tubes; for reel or tape-and-reel quantities, confirm the packing option at RFQ.