TSSOP (PW)-8-19.2 mm² 3 x 6.4

The LM57 device is a precision, dual-output, temperature switch with analog temperature sensor output for wide temperature industrial applications. The trip temperature (T_TRIP) is selected from 256 possible values in the range of –40°C to +150°C. The V_TEMP is a class AB analog voltage output that is proportional to temperature with a programmable negative temperature coefficient (NTC). Two external 1% resistors set the T_TRIP and V_TEMP slope. The digital and analog outputs enable protection and monitoring of system thermal events.

Built-in thermal hysteresis (T_HYST) prevents the digital outputs from oscillating. The T_OVER and T_OVER digital outputs will assert when the die temperature exceeds T_TRIP and will de-assert when the temperature falls below a temperature equal to T_TRIP minus T_HYST.

T_OVER is active-high with a push-pull structure. T_OVER is active-low with an open-drain structure. Tying T_OVER to TRIP-TEST will latch the output after it trips. The output can be cleared by forcing TRIP-TEST low. Driving the TRIP-TEST high will assert the digital outputs. A processor can check the state of T_OVER or T_OVER, confirming they changed to an active state. This allows for in-situ verification that the comparator and output circuitry are functional after system assembly. When TRIP-TEST is high, the trip-level reference voltage appears at the V_TEMP pin. The system could then use this voltage to calculate the threshold of the LM57.