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LINEAR TECHNOLOGY LM134 Series Data Sheet

Summary

The LM134 Series is a highly accurate, three-terminal current source designed for stable operation across currents ranging from 1mA to 10mA. Critically, it also functions as a precise temperature sensor because its regulated output current is directly proportional to absolute temperature. This manual details comprehensive electrical characteristics, coverage of applications—including remote sensing and constant-current biasing—and various package types. It is essential for engineers designing sensitive electronic systems requiring reliable and repeatable current regulation or accurate monitoring of ambient temperatures.

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LM134 Series

TEM PERATURE (°C)

Constant Current Source and Temperature Sensor

FEATURES DESCRIPTIO 1µA to 10m A Operation The LM134 is a three-terminal current source designed to 0.02%/V Regulation operate at current levels from 1µA to 10m A, as set by an 0.8V to 40V Operating Voltage external resistor. The device operates as a true two- Can be Used as Linear Temperature Sensor terminal current source, requiring no extra power connec-

Draws No Reverse Current tions or input signals. Regulation is typically 0.02%/V and Supplied in Standard Transistor Packages terminal-to-terminal voltage can range from 800m V to 40V. APPLICATIO S Because the operating current is directly proportional to absolute temperature in degrees Kelvin, the device will

Current Mode Temperature Sensing

also find wide applications as a temperature sensor. The

Constant Current Source for Shunt References

temperature dependence of the operating current is

Cold Junction Compensation

0.336%/°C at room temperature. For example, a device

Constant-Gain Bias for Bipolar Differential Stage

operating at 298µA will have a temperature coefficient of

Micropower Bias Networks

1µA/°C. The temperature dependence is extremely accu-

TE PE RA TU RE (° K)

Buffer for Photoconductive Cell

rate and repeatable. Devices specified as temperature

Current Limiter

sensors in the 100µA to 1m A range are the LM134-3, LM234-3 and the LM134-6, LM234-6, with the dash numbers indicating ±3°C and ±6°C accuracies, respec- tively. If a zero temperature coefficient current source is re- quired, this is easily achieved by adding a diode and a resistor., LTC and LT are registered trademarks of Linear Technology Corporation.

TYPICAL APPLICATIO Remote Temperature Sensor with Voltage Output Operating Current vs Temperature

VIN ≥ 5V

RSET = 226Ω

226Ω LM234-3 V–

TA01a

OPERATING CURRENT (µA)

TA01b

Page Summary Contents For LINEAR TECHNOLOGY LM134 Series Data Sheet

Page 1 LM134 Series TEM PERATURE (°C) Constant Current Source and Temperature Sensor FEATURES DESCRIPTIO 1µA to 10m A Operation The LM134 is a three-terminal current source designed to 0.02%/V Regulation ope...
Page 2 LM134 Series ABSOLUTE AXI RATI GS (Note 1) V+ to V– Forward Voltage Power Dissipation 200m W LM134 40V Operating Temperature Range LM134-3/LM134-6/LM234-3/ LM134 (OBSOLETE) –55°C to 125°C LM234-6/LM33...
Page 3 LM134 Series ELECTRICAL CHARACTERISTICS CURRENT SOURCE (Note 2) LM134 LM334 SYMBOL PARAMETER CONDITIONS MIN TYP MAX MIN TYP MAX UNITS ∆ISET Set Current Error, V+ = 2.5V 10µA ≤ ISET ≤ 1m A (Note 3) 1m ...
Page 4 ET ∆I SE TEM PERATURE (°C) IM PE DA NC (Ω LM134 Series TYPICAL PERFOR A CE CHARACTERISTICS Maximum Slew Rate for Output Impedance Linear Operation Start-Up RA TI SL EW AT (V /µ s) VO LT AG (m V) INPUT...
Page 5 LM134 Series APPLICATIO S I FOR ATIO Basic Theory of Operation the device is ±2% when the room temperature current is set to the exact desired value. The equivalent circuit of the LM134 is shown in Fi...
Page 6 LM134 Series APPLICATIO S I FOR ATIO Lead Resistance voltage across the 10k resistor will be 2.98V at 25°C, with a slope of 10m V/°C. The simplest way to convert this The sense voltage which determine...
Page 7 LM134 Series APPLICATIO S I FOR ATIO The two trims shown in Figure 3 are still intended to be a If higher accuracy is required, a two point calibration “one point” temperature calibration, where the z...
Page 8 LM134 Series TYPICAL APPLICATIO S Higher Output Current Low Output Impedance Thermometer Low Input Voltage Reference Driver VIN VIN VIN ≥ VREF + 200m V 2N4250 V+ V+ VOUT = VZ + 64m V AT 25°C V+ IOUT ≤...
Page 9 LM134 Series TYPICAL APPLICATIO S Precision 10n A Current Source Micropower 5V Reference 15V VIN = 6.5V TO 15V LM334 LM134 LM4250 VOUT = 5V 226k LT1004-1.2 R3 22MLT1004-1.2 BUFFERED LT1008 VOLTAGE OUT...
Page 10 LM134 Series PACKAGE DESCRIPTIO H Package 2-Lead and 3-Lead TO-46 Metal Can (Reference LTC DWG # 05-08-1340) (1.270) TYP 0.085 – 0.105 TYP PIN 1 FOR 3-LEAD PACKAGE ONLY REFERENCE PLANE 0.036 – 0.046 0...
Page 11 LM134 Series PACKAGE DESCRIPTIO S8 Package 8-Lead Plastic Small Outline (Narrow .150 Inch) (Reference LTC DWG # 05-08-1610) SO8 1298 (0.203 – 0.254) 0°– 8° TYP (0.355 – 0.483) (1.270) TYP BSC DIMENSIO...
Page 12 LM134 Series TYPICAL APPLICATIO S In-Line Current Limiter Generating Negative Output Impedance LM334 LM334 V– OP AMP –VIN TA18 *ZOUT ≈ –16 • R1(R1/VIN MUST NOT EXCEED ISET). *USE MINIMUM VALUE REQUIRE...

Manual Details

Brand Linear
Pages 12
File Size 155.09 KB
Published June 17, 2026
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Frequently Asked Questions

What is the operational current range for the LM134 series?

The device operates at current levels from 1mA to 10mA.

Can this device be used as a temperature sensor?

Yes, because the operating current is proportional to absolute temperature in degrees Kelvin. The dedicated models are LM134-3 and LM234-3, among others.

How accurate is the temperature sensing for certain devices (e.g., LM234-3)?

The accuracy varies by model, but the temperature dependence can be specified, with some versions offering -3°C or -6°C accuracies.

What are the minimum and maximum operating voltages?

The minimum operational voltage is 0.8V (for currents between 2mA and 100mA), and the maximum external resistor voltage is 40V.