A temperature sensor with single resistor set-point programming

An integrated circuit set point temperature controller has an open collector output which switches low at a temperature determined by an external resistor. The programming resistor may be determined from a universal formula relating resistance to desired trip temperature. The circuit is laser trimmed at a single temperature in manufacture to conform with the formula to better than 1/spl deg/C over a range between -40/spl deg/C and 150/spl deg/C. The circuit is low cost and includes temperature hysteresis, for well defined switching, and an optional output pull-up resistor.