Datasheet

ManualsBrandsTEXAS INSTRUMENTS ManualsPMICsPMIC - current control/management LM 334 Z Current source TO 92 3

LM134, LM234, LM334

www.ti.com

SNVS746C –MAY 2004–REVISED MARCH 2005

LM134/LM234/LM334 3-Terminal Adjustable Current Sources

Check for Samples: LM134, LM234, LM334

FEATURES

• Operates from 1V to 40V

• True 2-terminal operation

• 0.02%/V current regulation • Available as fully specified temperature sensor

• Programmable from 1μA to 10mA • ±3% initial accuracy

DESCRIPTION

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 guaranteed 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 guaranteed 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-46 hermetic, TO-92 and SO-8 plastic

packages.

Connection Diagrams

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

Package

−

Pin is electrically connected to case.

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 (24 pages)

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LM134, LM234, LM334 www.ti.com SNVS746C – MAY 2004 – REVISED MARCH 2005 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 SNVS746C – MAY 2004 – REVISED MARCH 2005 www.ti.com Figure 3. TO-46 Metal Can Package (Bottom View) Figure 4. TO-92 Plastic Package (Bottom View) 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 SNVS746C – MAY 2004 – REVISED MARCH 2005 Electrical Characteristics Parameter (1) Conditions LM134/LM234 Min Set Current Error, V+=2.5V, (2) Typ Min Typ Units Max 10μA ≤ ISET ≤ 1mA 3 6 % 1mA < ISET ≤ 5mA 5 8 % 12 % 2μA ≤ ISET < 10μA Ratio of Set Current to 100μA ≤ ISET ≤ 1mA Bias Current 1mA ≤ ISET ≤ 5mA Minimum Operating Voltage LM334 Max 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.
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LM134, LM234, LM334 SNVS746C – MAY 2004 – REVISED MARCH 2005 Electrical Characteristics www.ti.com (1) Parameter Conditions LM234-3 Min Set Current Error, V+=2.5V, (2) Typ 100μA ≤ ISET ≤ 1mA LM234-6 Max Min Typ ±1 Units Max ±2 % ±6 °C TJ = 25° Equivalent Temperature Error Ratio of Set Current to ±3 100μA ≤ ISET ≤ 1mA 14 18 26 14 18 26 Bias Current Minimum Operating Voltage 100μA ISET ≤ 1mA Average Change in Set Current 100μA ≤ ISET ≤ 1mA with Input Voltage 1.5 ≤ V+ ≤ 5V 0.
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LM134, LM234, LM334 www.ti.com SNVS746C – MAY 2004 – REVISED MARCH 2005 Typical Performance Characteristics Output Impedance Maximum Slew Rate Linear Operation Start-Up Transient Response Voltage Across RSET (VR) Current Noise Turn-On Voltage Ratio of ISET to IBIAS 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.
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LM134, LM234, LM334 SNVS746C – MAY 2004 – REVISED MARCH 2005 www.ti.com Figure 5. Basic Current Source A graph showing the ratio of these two currents is supplied under Ratio of ISET to IBIAS in the Typical Performance Characteristics section. The current flowing through RSET is determined by VR, which is approximately 214μV/°K (64 mV/298°K ∼ 214μV/°K).
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LM134, LM234, LM334 www.ti.com SNVS746C – MAY 2004 – REVISED MARCH 2005 LEAD RESISTANCE The sense voltage which determines operating current of the LM134 is less than 100mV. At this level, thermocouple or lead resistance effects should be minimized by locating the current setting resistor physically close to the device. Sockets should be avoided if possible. It takes only 0.7Ω contact resistance to reduce output current by 1% at the 1 mA level.
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LM134, LM234, LM334 SNVS746C – MAY 2004 – REVISED MARCH 2005 www.ti.com Figure 7. Zero Tempco Current Source The set current (ISET) is the sum of I1 and I2, each contributing approximately 50% of the set current, and IBIAS. IBIAS is usually included in the I1 term by increasing the VR value used for calculations by 5.9%. (See CALCULATING RSET.) (5) The first step is to minimize the tempco of the circuit, using the following equations.
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LM134, LM234, LM334 www.ti.com SNVS746C – MAY 2004 – REVISED MARCH 2005 EXAMPLE: A 1mA, Zero-Tempco Current Source First, solve for R1 and R2: (9) The values of R1 and R2 can be changed to standard 1% resistor values (R1 = 133Ω and R2 = 1.33kΩ) with less than a 0.75% error. If the forward voltage drop of the diode was 0.65V instead of the estimate of 0.6V (an error of 8%), the actual set current will be (10) an error of less than 5%.
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LM134, LM234, LM334 SNVS746C – MAY 2004 – REVISED MARCH 2005 www.ti.com Figure 9. 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. This negative resistance can be reduced by a factor of 5 or more by inserting an equivalent resistor R3 = (R2/16) in series with the output. Figure 10. Low Output Impedance Thermometer Figure 11.
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LM134, LM234, LM334 www.ti.com SNVS746C – MAY 2004 – REVISED MARCH 2005 *Select R1 and C1 for optimum stability Figure 12. Higher Output Current Figure 13. Basic 2-Terminal Current Source Figure 14.
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LM134, LM234, LM334 SNVS746C – MAY 2004 – REVISED MARCH 2005 www.ti.com Figure 15. Low Input Voltage Reference Driver Figure 16. Ramp Generator *Select ratio of R1 to R2 to obtain zero temperature drift Figure 17. 1.
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LM134, LM234, LM334 www.ti.com SNVS746C – MAY 2004 – REVISED MARCH 2005 *Select ratio of R1 to R2 for zero temperature drift Figure 18. 1.2V Regulator with 1.8V Minimum Input Figure 19. Zener Biasing *For ±10% adjustment, select RSET10% high, and make R1 ≈ 3 RSET Figure 20.
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LM134, LM234, LM334 SNVS746C – MAY 2004 – REVISED MARCH 2005 www.ti.com Figure 21. Buffer for Photoconductive Cell *Select Q1 or Q2 to ensure at least 1V across the LM134. Vp (1 − ISET/IDSS) ≥ 1.2V. Figure 22. FET Cascoding for Low Capacitance and/or Ultra High Output Impedance *ZOUT ≈ −16 • R1 (R1/VIN must not exceed ISET) Figure 23.
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LM134, LM234, LM334 www.ti.com SNVS746C – MAY 2004 – REVISED MARCH 2005 *Use minimum value required to ensure stability of protected device. This minimizes inrush current to a direct short. Figure 24.
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PACKAGE OPTION ADDENDUM www.ti.
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PACKAGE OPTION ADDENDUM www.ti.com 17-Nov-2012 Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.
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PACKAGE MATERIALS INFORMATION www.ti.com 17-Nov-2012 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 17-Nov-2012 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) LM334MX SOIC D 8 2500 349.0 337.0 45.0 LM334MX/NOPB SOIC D 8 2500 349.0 337.0 45.0 LM334SMX SOIC D 8 2500 349.0 337.0 45.0 LM334SMX/NOPB SOIC D 8 2500 349.0 337.0 45.
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MECHANICAL DATA NDV0003H H03H (Rev F) www.ti.
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MECHANICAL DATA MSOT002A – OCTOBER 1994 – REVISED NOVEMBER 2001 LP (O-PBCY-W3) PLASTIC CYLINDRICAL PACKAGE 0.205 (5,21) 0.175 (4,44) 0.165 (4,19) 0.125 (3,17) DIA 0.210 (5,34) 0.170 (4,32) Seating Plane 0.157 (4,00) MAX 0.050 (1,27) C 0.500 (12,70) MIN 0.104 (2,65) FORMED LEAD OPTION 0.022 (0,56) 0.016 (0,41) 0.016 (0,41) 0.014 (0,35) STRAIGHT LEAD OPTION D 0.135 (3,43) MIN 0.105 (2,67) 0.095 (2,41) 0.055 (1,40) 0.045 (1,14) 1 2 3 0.105 (2,67) 0.080 (2,03) 0.105 (2,67) 0.
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MECHANICAL DATA MSOT002A – OCTOBER 1994 – REVISED NOVEMBER 2001 LP (O-PBCY-W3) PLASTIC CYLINDRICAL PACKAGE 0.539 (13,70) 0.460 (11,70) 1.260 (32,00) 0.905 (23,00) 0.650 (16,50) 0.610 (15,50) 0.020 (0,50) MIN 0.098 (2,50) 0.384 (9,75) 0.335 (8,50) 0.748 (19,00) 0.217 (5,50) 0.433 (11,00) 0.335 (8,50) 0.748 (19,00) 0.689 (17,50) 0.114 (2,90) 0.094 (2,40) 0.114 (2,90) 0.094 (2,40) 0.169 (4,30) 0.146 (3,70) DIA 0.266 (6,75) 0.234 (5,95) 0.512 (13,00) 0.
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