Datasheet

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LM134, LM234, LM334

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SNVS746E –MARCH 2000–REVISED MAY 2013

LM134/LM234/LM334 3-Terminal Adjustable Current Sources

Check for Samples: LM134, LM234, LM334

FEATURES

The sense voltage used to establish operating current

• Operates From 1V to 40V

in the LM134 is 64mV at 25°C and is directly

• 0.02%/V Current Regulation

proportional to absolute temperature (°K). The

• Programmable From 1μA to 10mA

simplest one external resistor connection, then,

generates a current with ≈+0.33%/°C temperature

• True 2-Terminal Operation

dependence. Zero drift operation can be obtained by

• Available as Fully Specified Temperature

adding one extra resistor and a diode.

Sensor

Applications for the current sources include bias

• ±3% Initial Accuracy

networks, surge protection, low power reference,

ramp generation, LED driver, and temperature

DESCRIPTION

sensing. The LM234-3 and LM234-6 are specified as

The LM134/LM234/LM334 are 3-terminal adjustable

true temperature sensors with ensured initial

current sources featuring 10,000:1 range in operating

accuracy of ±3°C and ±6°C, respectively. These

current, excellent current regulation and a wide

devices are ideal in remote sense applications

dynamic voltage range of 1V to 40V. Current is

because series resistance in long wire runs does not

established with one external resistor and no other

affect accuracy. In addition, only 2 wires are required.

parts are required. Initial current accuracy is ±3%.

The LM134 is specified over a temperature range of

The LM134/LM234/LM334 are true floating current

−55°C to +125°C, the LM234 from −25°C to +100°C

sources with no separate power supply connections.

and the LM334 from 0°C to +70°C. These devices

In addition, reverse applied voltages of up to 20V will

are available in TO hermetic, TO-92 and SOIC-8

draw only a few dozen microamperes of current,

plastic packages.

allowing the devices to act as both a rectifier and

current source in AC applications.

Connection Diagrams

Figure 1. SOIC-8 Surface Mount Package Figure 2. SOIC-8 Alternative Pinout Surface Mount

Package

(LM334M; LM334M/NOPB; LM334MX;

LM334MX/NOPB) (LM334SM; LM334SM/NOPB; LM334SMX;

LM334SMX/NOPB)

See Package Number D

Figure 3. TO Metal Can Package (Bottom View) Figure 4. TO-92 Plastic Package (Bottom View)

See Package Number NDV See Package Number LP

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of

Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

2All trademarks are the property of their respective owners.

PRODUCTION DATA information is current as of publication date.

Products conform to specifications per the terms of the Texas

Instruments standard warranty. Production processing does not

necessarily include testing of all parameters.

Summary of content (26 pages)

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LM134, LM234, LM334 www.ti.com SNVS746E – MARCH 2000 – REVISED MAY 2013 LM134/LM234/LM334 3-Terminal Adjustable Current Sources Check for Samples: LM134, LM234, LM334 FEATURES 1 • • • • • 2 • Operates From 1V to 40V 0.
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LM134, LM234, LM334 SNVS746E – MARCH 2000 – REVISED MAY 2013 www.ti.com These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates.
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LM134, LM234, LM334 www.ti.com SNVS746E – MARCH 2000 – REVISED MAY 2013 Electrical Characteristics (1) Parameter Conditions Set Current Error, V+=2.5V (2) LM134/LM234 Min Typ 6 % 8 % 12 % 8 14 18 23 14 14 18 26 14 2 μA≤ISET≤100 μA 18 2μA ≤ ISET ≤ 100μA 0.8 0.8 V 100μA < ISET ≤ 1mA 0.9 0.9 V 1mA < ISET ≤ 5mA 1mA < ISET ≤ 5mA 23 18 1.0 26 1.0 V 1.5 ≤ V+ ≤ 5V 0.02 0.05 0.02 0.1 %/V 5V ≤ V+ ≤ 40V 0.01 0.03 0.01 0.05 %/V 1.5V ≤ V ≤ 5V 0.
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LM134, LM234, LM334 SNVS746E – MARCH 2000 – REVISED MAY 2013 www.ti.com Typical Performance Characteristics 4 Output Impedance Maximum Slew Rate Linear Operation Figure 5. Figure 6. Start-Up Transient Response Figure 7. Figure 8. Voltage Across RSET (VR) Current Noise Figure 9. Figure 10.
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LM134, LM234, LM334 www.ti.com SNVS746E – MARCH 2000 – REVISED MAY 2013 Typical Performance Characteristics (continued) Turn-On Voltage Ratio of ISET to IBIAS Figure 11. Figure 12.
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LM134, LM234, LM334 SNVS746E – MARCH 2000 – REVISED MAY 2013 www.ti.com APPLICATION HINTS The LM134 has been designed for ease of application, but a general discussion of design features is presented here to familiarize the designer with device characteristics which may not be immediately obvious. These include the effects of slewing, power dissipation, capacitance, noise, and contact resistance.
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LM134, LM234, LM334 www.ti.com SNVS746E – MARCH 2000 – REVISED MAY 2013 Shunt Capacitance In certain applications, the 15 pF shunt capacitance of the LM134 may have to be reduced, either because of loading problems or because it limits the AC output impedance of the current source. This can be easily accomplished by buffering the LM134 with an FET as shown in the applications. This can reduce capacitance to less than 3 pF and improve regulation by at least an order of magnitude.
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LM134, LM234, LM334 SNVS746E – MARCH 2000 – REVISED MAY 2013 www.ti.com Application as a Zero Temperature Coefficent Current Source Adding a diode and a resistor to the standard LM134 configuration can cancel the temperature-dependent characteristic of the LM134. The circuit shown in Figure 15 balances the positive tempco of the LM134 (about +0.23 mV/°C) with the negative tempco of a forward-biased silicon diode (about −2.5 mV/°C). Figure 15.
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LM134, LM234, LM334 www.ti.com SNVS746E – MARCH 2000 – REVISED MAY 2013 (8) This circuit will eliminate most of the LM134's temperature coefficient, and it does a good job even if the estimates of the diode's characteristics are not accurate (as the following example will show). For lowest tempco with a specific diode at the desired ISET, however, the circuit should be built and tested over temperature. If the measured tempco of ISET is positive, R2 should be reduced.
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LM134, LM234, LM334 SNVS746E – MARCH 2000 – REVISED MAY 2013 www.ti.com Typical Applications *Select R3 = VREF/583μA. VREF may be any stable positive voltage ≥ 2V Trim R3 to calibrate Figure 16. Ground Referred Fahrenheit Thermometer Figure 17. Terminating Remote Sensor for Voltage Output *Output impedance of the LM134 at the “R” pin is approximately where R2 is the equivalent external resistance connected from the V− pin to ground.
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LM134, LM234, LM334 www.ti.com SNVS746E – MARCH 2000 – REVISED MAY 2013 Figure 19. Low Output Impedance Thermometer *Select R1 and C1 for optimum stability Figure 20. Higher Output Current Figure 21.
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LM134, LM234, LM334 SNVS746E – MARCH 2000 – REVISED MAY 2013 www.ti.com Figure 22. Micropower Bias Figure 23. Low Input Voltage Reference Driver Figure 24.
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LM134, LM234, LM334 www.ti.com SNVS746E – MARCH 2000 – REVISED MAY 2013 *Select ratio of R1 to R2 to obtain zero temperature drift Figure 25. 1.2V Reference Operates on 10 μA and 2V *Select ratio of R1 to R2 for zero temperature drift Figure 26. 1.2V Regulator with 1.8V Minimum Input Figure 27.
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LM134, LM234, LM334 SNVS746E – MARCH 2000 – REVISED MAY 2013 www.ti.com *For ±10% adjustment, select RSET10% high, and make R1 ≈ 3 RSET Figure 28. Alternate Trimming Technique Figure 29. Buffer for Photoconductive Cell *Select Q1 or Q2 to ensure at least 1V across the LM134. Vp (1 − ISET/IDSS) ≥ 1.2V.
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LM134, LM234, LM334 www.ti.com SNVS746E – MARCH 2000 – REVISED MAY 2013 Figure 30. FET Cascoding for Low Capacitance and/or Ultra High Output Impedance *ZOUT ≈ −16 • R1 (R1/VIN must not exceed ISET) Figure 31. Generating Negative Output Impedance *Use minimum value required to ensure stability of protected device. This minimizes inrush current to a direct short. Figure 32.
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LM134, LM234, LM334 SNVS746E – MARCH 2000 – REVISED MAY 2013 www.ti.
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LM134, LM234, LM334 www.ti.com SNVS746E – MARCH 2000 – REVISED MAY 2013 REVISION HISTORY Changes from Revision C (April 2013) to Revision D • Page Changed layout of National Data Sheet to TI format ..........................................................................................................
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PACKAGE OPTION ADDENDUM www.ti.
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PACKAGE OPTION ADDENDUM www.ti.com 4-May-2014 (2) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability information and additional product content details. TBD: The Pb-Free/Green conversion plan has not been defined.
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PACKAGE MATERIALS INFORMATION www.ti.com 29-May-2013 TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Package Pins Type Drawing SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant LM334MX SOIC D 8 2500 330.0 12.4 6.5 5.4 2.0 8.0 12.0 Q1 LM334MX/NOPB SOIC D 8 2500 330.0 12.4 6.5 5.4 2.0 8.0 12.0 Q1 LM334SMX SOIC D 8 2500 330.0 12.4 6.5 5.4 2.0 8.0 12.0 Q1 LM334SMX/NOPB SOIC D 8 2500 330.
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PACKAGE MATERIALS INFORMATION www.ti.com 29-May-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) LM334MX SOIC D 8 2500 367.0 367.0 35.0 LM334MX/NOPB SOIC D 8 2500 367.0 367.0 35.0 LM334SMX SOIC D 8 2500 367.0 367.0 35.0 LM334SMX/NOPB SOIC D 8 2500 367.0 367.0 35.
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MECHANICAL DATA NDV0003H H03H (Rev F) www.ti.
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