What the thermal detection IC does on the board
The TCTH021BE,LF(CT is a thermal detection IC from Toshiba's TCTH0xxxE series — it monitors a single voltage threshold at 0.5V and asserts an open-drain or open-collector output when the temperature at the die exceeds the internal trip point. The 214µs typical reset timeout means the output automatically recovers after the over-temperature condition clears, without requiring an external reset pin or supervisor.
Package and footprint for layout
Housed in a 5-pin SOT-553 package (supplier device package ESV), the TCTH021BE,LF(CT occupies roughly 1.6 mm × 1.6 mm of board area — small enough to place near the hot component it monitors. Surface-mount mounting with tape-and-reel or cut-tape packaging; the 0.5V threshold is internally fixed, so no external resistor divider is needed for the sense input.