All trademarks are the property of their respective owners.
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 | AN-256 Circuitry for Inexpensive Relative Humidity Measurement (Rev. B) | 06 May 2013 | ||
| Application note | AN-240 Wide-Range Current-to-Frequency Converters (Rev. B) | 29 Apr 2013 | ||
| Application note | AN-C V/F Converter ICs Handle Frequency-to-Voltage Needs (Rev. B) | 23 Apr 2013 | ||
| More literature | Die D/S LM334 MWC 3-Terminal Adj Current Source | 21 Sep 2012 | ||
| Application note | TO-92 Packing Options / Ordering Instructions (Rev. A) | 23 Jun 2010 | ||
| Application note | Applying a New Precision Op Amp | 04 Oct 2004 |
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 |
|---|---|---|
| SOIC (D) | 8 | Ultra Librarian |
| TO-92 (LP) | 3 | Ultra Librarian |
| WAFERSALE (YS) | — |
Content is provided "as is" by TI and community contributors and does not constitute TI specifications. See terms of use.
If you have questions about quality, packaging or ordering TI products, see TI support.