The LM94021 is a precision analog output CMOS integrated-circuit temperature sensor that
operates at a supply voltage as low as 1.5V. While operating over the wide temperature range of
−50°C to +150°C, the LM94021 delivers an output voltage that is inversely proportional to measured
temperature. The LM94021's low supply current makes it ideal for battery-powered systems as well as
general temperature sensing applications.
Two logic inputs, Gain Select 1 (GS1) and Gain Select 0 (GS0), select the gain of the
temperature-to-voltage output transfer function. Four slopes are selectable: −5.5 mV/°C, −8.2
mV/°C, −10.9 mV/°C, and −13.6 mV/°C. In the lowest gain configuration (GS1 and GS0 both tied low),
the LM94021 can operate with a 1.5V supply while measuring temperature over the full −50°C to
+150°C operating range. Tying both inputs high causes the transfer function to have the largest
gain of −13.6 mV/°C for maximum temperature sensitivity. The gain-select inputs can be tied
directly to VDD or Ground without any pull-up or pull-down resistors,
reducing component count and board area. These inputs can also be driven by logic signals allowing
the system to optimize the gain during operation or system diagnostics.