-15°C cold-trip thermostat in SOT-23-5
The Microchip Technology TC6503N015VCTTR is a factory-programmed temperature switch that asserts an Active Low open-drain output when the die temperature drops below -15°C. This is a cold-trip threshold device — the /UnderTemp output pulls low when the monitored point falls below the trip point, with a selectable hysteresis window to prevent chatter around the threshold. Accuracy is rated at ±4°C, which for a -15°C trip means the actual switch point sits between -11°C and -19°C worst-case. That is tight enough for cold-chain monitoring or frost-detection circuits where a few degrees of margin are acceptable, but not for precision thermal-shutdown where tighter tolerance is required.
Supply and output drive
The open-drain output sinks 20 mA max — enough to drive a small relay coil, an LED indicator, or a logic-level input on a microcontroller without a buffer. The output signal is Active Low with an open-drain stage, meaning the pin floats high when the temperature is above -15°C and pulls to ground when the threshold is crossed. This is the standard interface for wired-OR fault buses or interrupt lines on a processor GPIO.
Temperature range and environment
The device is specified for an operating temperature range of -55°C to 135°C, which covers industrial, automotive under-hood, and cold-chain extremes. The -15°C trip point sits well within this envelope, so the thermostat itself does not limit the system ambient range. Surface-mount assembly in an SOT-23-5 package means the sensor sits directly on the PCB, sensing board temperature rather than air temperature. For cold-trip applications, the thermal coupling to the monitored component — not ambient air — is what determines response time.