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The LM134/LM234/LM334 are 3-terminal adjustable current sources featuring 10,000:1 range in operating current, excellent current regulation and a wide dynamic voltage range of 1V to 40V. Current is established with one external resistor and no other parts are required. Initial current accuracy is ±3%. The LM134/LM234/LM334 are true floating current sources with no separate power supply connections. In addition, reverse applied voltages of up to 20V will draw only a few dozen microamperes of current, allowing the devices to act as both a rectifier and current source in AC applications.
The sense voltage used to establish operating current in the LM134 is 64mV at 25°C and is directly proportional to absolute temperature (°K). The simplest one external resistor connection, then, generates a current with ≈+0.33%/°C temperature dependence. Zero drift operation can be obtained by adding one extra resistor and a diode.
Applications for the current sources include bias networks, surge protection, low power reference, ramp generation, LED driver, and temperature sensing. The LM234-3 and LM234-6 are specified as true temperature sensors with ensured initial accuracy of ±3°C and ±6°C, respectively. These devices are ideal in remote sense applications because series resistance in long wire runs does not affect accuracy. In addition, only 2 wires are required.
The LM134 is specified over a temperature range of −55°C to +125°C, the LM234 from −25°C to +100°C and the LM334 from 0°C to +70°C. These devices are available in TO hermetic, TO-92 and SOIC-8 plastic packages.
| Type | Title | Date | ||
|---|---|---|---|---|
| * | Data sheet | LM134/LM234/LM334 3-Terminal Adjustable Current Sources datasheet (Rev. E) | 20 Jun 2013 | |
| E-book | Tips and tricks for designing with voltage references (Rev. A) | 07 May 2021 | ||
| Application note | Precision Current Sources and Sinks Using Voltage References | 30 Jun 2020 | ||
| E-book | Voltage Supervisor and Reset ICs: Tips, Tricks and Basics | 28 Jun 2019 | ||
| Application note | TO-92 Packing Options / Ordering Instructions (Rev. A) | 23 Jun 2010 |
For additional terms or required resources, click any title below to view the detail page where available.
This external resistor quick-start calculator tool lets you easily calculate valid external resistor values relative to voltage reference, supply and load-current bounds. With these inputs, you can instantly view the resulting calculations and use the color-coded indications to understand (...)
| Package | Pins | CAD symbols, footprints & 3D models |
|---|---|---|
| TO-92 (LP) | 3 | Ultra Librarian |
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