The LM134 is a three-terminal current source designed to operate at current levels from 1µA to 10mA, as set by an external resistor. The device operates as a true two terminal current source, requiring no extra power connections or input signals. Regulation is typically 0.02%/V and terminal-to-terminal voltage can range from 800mV to 40V.Because the operating current is directly proportional to absolute temperature in degrees Kelvin, the device will also find wide applications as a temperature sensor. The temperature dependence of the operating current is 0.336%/°C at room temperature. For example, a device operating at 298µA will have a temperature coefficient of 1mA/°C. The temperature dependence is extremely accurate and repeatable. Devices specified as temperature sensors in the 100µA to 1mA range are the LM134-3, LM234-3 and the LM134-6, LM234-6, with the dash numbers indicating ±3°C and ±6°C accuracies, respectively.If a zero temperature coefficient current source is required, this is easily achieved by adding a diode and a resistor.ApplicationsCurrent Mode Temperature SensingConstant Current Source for Shunt ReferencesCold Junction Compensation Constant-Gain Bias for Bipolar Differential StageMicropower Bias NetworksBuffer for Photoconductive CellCurrent Limiter