LM34

The LM34 series devices are precision integrated-circuit temperature sensors, whose output voltage is linearly proportional to the Fahrenheit temperature. The LM34 device has an advantage over linear temperature sensors calibrated in degrees Kelvin, because the user is not required to subtract a large constant voltage from its output to obtain convenient Fahrenheit scaling. The LM34 device does not require any external calibration or trimming to provide typical accuracies of ±1/2°F at room temperature and ±1-1⁄2°F over a full −50°F to 300°F temperature range. Lower cost is assured by trimming and calibration at the wafer level. The low output impedance, linear output, and precise inherent calibration of the LM34 device makes interfacing to readout or control circuitry especially easy. It can be used with single power supplies or with plus and minus supplies. Because the LM34 device draws only 75 µA from its supply, the device has very low self-heating, less than 0.2°F in still air.

The LM34 device is rated to operate over a −50°F to 300°F temperature range, while the LM34C is rated for a −40°F to 230°F range (0°F with improved accuracy). The LM34 devices are series is available packaged in hermetic TO-46 transistor packages; while the LM34C, LM34CA, and LM34D are available in the plastic TO-92 transistor package. The LM34D device is available in an 8-lead, surface-mount, small-outline package. The LM34 device is a complement to the LM35 device (Centigrade) temperature sensor.