3-Terminal Adjustable Current Sources

A part  of stock list

Feature

■ 1µA to 10mA Operation

■ 0.02%/V Regulation

■ 0.8V to 40V Operating Voltage

■ Can be Used as Linear Temperature Sensor

■ Draws No Reverse Current

■ Supplied in Standard Transistor Packages

Applicataion

■ Current Mode Temperature Sensing

■ Constant Current Source for Shunt References

■ Cold Junction Compensation

■ Constant-Gain Bias for Bipolar Differential Stage

■ Micropower Bias Networks

■ Buffer for Photoconductive Cell

■ Current Limiter

Description

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 twoterminal 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 1µA/°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.