Proyecto Fin de Carrerabibing.us.es/proyectos/abreproy/11385/descargar_fichero/1%2F10_Anexo.pdf · series (3A) and LM138 series (5A) data sheets. For the negative complement, see

Anexo

86

Anexo

• Datasheet de National Semiconductor: LM317

• Datasheet de National Semiconductor: LM334

• Datasheet de Coilcraft: WideBandRFTransformers

LM117/LM317A/LM3173-Terminal Adjustable RegulatorGeneral DescriptionThe LM117 series of adjustable 3-terminal positive voltageregulators is capable of supplying in excess of 1.5A over a1.2V to 37V output range. They are exceptionally easy touse and require only two external resistors to set the outputvoltage. Further, both line and load regulation are better thanstandard fixed regulators. Also, the LM117 is packaged instandard transistor packages which are easily mounted andhandled.

In addition to higher performance than fixed regulators, theLM117 series offers full overload protection available only inIC’s. Included on the chip are current limit, thermal overloadprotection and safe area protection. All overload protectioncircuitry remains fully functional even if the adjustment termi-nal is disconnected.

Normally, no capacitors are needed unless the device is situ-ated more than 6 inches from the input filter capacitors inwhich case an input bypass is needed. An optional outputcapacitor can be added to improve transient response. Theadjustment terminal can be bypassed to achieve very highripple rejection ratios which are difficult to achieve with stan-dard 3-terminal regulators.

Besides replacing fixed regulators, the LM117 is useful in awide variety of other applications. Since the regulator is“floating” and sees only the input-to-output differential volt-

age, supplies of several hundred volts can be regulated aslong as the maximum input to output differential is not ex-ceeded, i.e., avoid short-circuiting the output.

Also, it makes an especially simple adjustable switchingregulator, a programmable output regulator, or by connectinga fixed resistor between the adjustment pin and output, theLM117 can be used as a precision current regulator. Sup-plies with electronic shutdown can be achieved by clampingthe adjustment terminal to ground which programs the out-put to 1.2V where most loads draw little current.

For applications requiring greater output current, see LM150series (3A) and LM138 series (5A) data sheets. For thenegative complement, see LM137 series data sheet.

Featuresn Guaranteed 1% output voltage tolerance (LM317A)n Guaranteed max. 0.01%/V line regulation (LM317A)n Guaranteed max. 0.3% load regulation (LM117)n Guaranteed 1.5A output currentn Adjustable output down to 1.2Vn Current limit constant with temperaturen P+ Product Enhancement testedn 80 dB ripple rejectionn Output is short-circuit protected

Typical Applications LM117 Series Packages and PowerCapability

Part Number Rated Design

Suffix Package Power Load

Dissipation Current

K TO-3 20W 1.5A

H TO-39 2W 0.5A

T TO-220 20W 1.5A

E LCC 2W 0.5A

S TO-263 4W 1.5A

MP SOT-223 2W 1A

Comparison between SOT-223 andD-Pak (TO-252) Packages

1.2V–25V Adjustable Regulator

DS009063-1

Full output current not available at high input-output voltages*Needed if device is more than 6 inches from filter capacitors.†Optional—improves transient response. Output capacitors in the range

of 1 µF to 1000 µF of aluminum or tantalum electrolytic are commonlyused to provide improved output impedance and rejection of transients.

DS009063-54

Scale 1:1

February 1998

LM117/LM

317A/LM

3173-Term

inalAdjustable

Regulator

© 1998 National Semiconductor Corporation DS009063 www.national.com

Absolute Maximum Ratings (Note 1)

If Military/Aerospace specified devices are required,please contact the National Semiconductor Sales Office/Distributors for availability and specifications.

Power Dissipation Internally LimitedInput-Output Voltage Differential +40V, −0.3VStorage Temperature −65˚C to +150˚CLead Temperature

Metal Package (Soldering, 10 seconds) 300˚CPlastic Package (Soldering, 4 seconds) 260˚C

ESD Tolerance (Note 5) 3 kV

Operating Temperature RangeLM117 −55˚C ≤ TJ ≤ +150˚CLM317A −40˚C ≤ TJ ≤ +125˚CLM317 0˚C ≤ TJ ≤ +125˚C

PreconditioningThermal Limit Burn-In All Devices 100%

Electrical Characteristics (Note 3)Specifications with standard type face are for TJ = 25˚C, and those with boldface type apply over full Operating Tempera-ture Range . Unless otherwise specified, VIN − VOUT = 5V, and IOUT = 10 mA.

Parameter Conditions LM117 (Note 2) Units

Min Typ Max

Reference Voltage V

3V ≤ (VIN − VOUT) ≤ 40V, 1.20 1.25 1.30 V

10 mA ≤ IOUT ≤ IMAX, P ≤ PMAX

Line Regulation 3V ≤ (VIN − VOUT) ≤ 40V (Note 4) 0.01 0.02 %/V

0.02 0.05 %/V

Load Regulation 10 mA ≤ IOUT ≤ IMAX (Note 4) 0.1 0.3 %

0.3 1 %

Thermal Regulation 20 ms Pulse 0.03 0.07 %/W

Adjustment Pin Current 50 100 µA

Adjustment Pin Current Change 10 mA ≤ IOUT ≤ IMAX 0.2 5 µA

3V ≤ (VIN − VOUT) ≤ 40V

Temperature Stability TMIN ≤ TJ ≤ TMAX 1 %

Minimum Load Current (VIN − VOUT) = 40V 3.5 5 mA

Current Limit (VIN − VOUT) ≤ 15V

K Package 1.5 2.2 3.4 A

H, K Packages 0.5 0.8 1.8 A

(VIN − VOUT) = 40V

K Package 0.3 0.4 A

H, K Packages 0.15 0.2 A

RMS Output Noise, % of VOUT 10 Hz ≤ f ≤ 10 kHz 0.003 %

Ripple Rejection Ratio VOUT = 10V, f = 120 Hz, 65 dB

CADJ = 0 µF

VOUT = 10V, f = 120 Hz, 66 80 dB

CADJ = 10 µF

Long-Term Stability TJ = 125˚C, 1000 hrs 0.3 1 %

Thermal Resistance, K Package 2.3 3 ˚C/W

Junction-to-Case H Package 12 15 ˚C/W

E Package ˚C/W

Thermal Resistance, Junction- K Package 35 ˚C/W

to-Ambient (No Heat Sink) H Package 140 ˚C/W

E Package ˚C/W

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Electrical Characteristics (Note 3)Specifications with standard type face are for TJ = 25˚C, and those with boldface type apply over full Operating Tempera-ture Range . Unless otherwise specified, VIN − VOUT = 5V, and IOUT = 10 mA.

Parameter Conditions LM317A LM317 Units

Min Typ Max Min Typ Max

Reference Voltage 1.238 1.250 1.262 V

3V ≤ (VIN − VOUT) ≤ 40V, 1.225 1.250 1.270 1.20 1.25 1.30 V

10 mA ≤ IOUT ≤ IMAX, P ≤ PMAX

Line Regulation 3V ≤ (VIN − VOUT) ≤ 40V (Note 4) 0.005 0.01 0.01 0.04 %/V

0.01 0.02 0.02 0.07 %/V

Load Regulation 10 mA ≤ IOUT ≤ IMAX (Note 4) 0.1 0.5 0.1 0.5 %

0.3 1 0.3 1.5 %

Thermal Regulation 20 ms Pulse 0.04 0.07 0.04 0.07 %/W

Adjustment Pin Current 50 100 50 100 µA

Adjustment Pin CurrentChange

10 mA ≤ IOUT ≤ IMAX 0.2 5 0.2 5 µA

3V ≤ (VIN − VOUT) ≤ 40V

Temperature Stability TMIN ≤ TJ ≤ TMAX 1 1 %

Minimum Load Current (VIN − VOUT) = 40V 3.5 10 3.5 10 mA

Current Limit (VIN − VOUT) ≤ 15V

K, T, S Packages 1.5 2.2 3.4 1.5 2.2 3.4 A

H Package 0.5 0.8 1.8 0.5 0.8 1.8 A

(VIN − VOUT) = 40V

K, T, S Packages 0.15 0.4 0.15 0.4 A

H Package 0.075 0.2 0.075 0.2 A

RMS Output Noise, % of VOUT 10 Hz ≤ f ≤ 10 kHz 0.003 0.003 %

Ripple Rejection Ratio VOUT = 10V, f = 120 Hz, 65 65 dB

CADJ = 0 µF

VOUT = 10V, f = 120 Hz, 66 80 66 80 dB

CADJ = 10 µF

Long-Term Stability TJ = 125˚C, 1000 hrs 0.3 1 0.3 1 %

Thermal Resistance, Junction- K Package 2.3 3 ˚C/W

to-Case H Package 12 15 12 15 ˚C/W

T Package 4 5 4 ˚C/W

Thermal Resistance, Junction- K Package 35 35 ˚C/W

to-Ambient (No Heat Sink) H Package 140 140 ˚C/W

T Package 50 50 ˚C/W

S Package (Note 6) 50 50 ˚C/W

Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is in-tended to be functional, but do not guarantee specific performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics. Theguaranteed specifications apply only for the test conditions listed.

Note 2: Refer to RETS117H drawing for the LM117H, or the RETS117K for the LM117K military specifications.

Note 3: Although power dissipation is internally limited, these specifications are applicable for maximum power dissipations of 2W for the TO-39 and SOT-223 and20W for the TO-3, TO-220, and TO-263. IMAX is 1.5A for the TO-3, TO-220, and TO-263 packages and 0.5A for the TO-39 package. All limits (i.e., the numbers inthe Min. and Max. columns) are guaranteed to National’s AOQL (Average Outgoing Quality Level).

Note 4: Regulation is measured at a constant junction temperature, using pulse testing with a low duty cycle. Changes in output voltage due to heating effects arecovered under the specifications for thermal regulation.

Note 5: Human body model, 100 pF discharged through a 1.5 kΩ resistor.

Note 6: If the TO-263 package is used, the thermal resistance can be reduced by increasing the PC board copper area thermally connected to the package. If theSOT-223 package is used, the thermal resistance can be reduced by increasing the PC board copper area (see applications hints for heatsinking).

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Typical Performance CharacteristicsOutput Capacitor = 0 µF unless otherwise noted

Load Regulation

DS009063-37

Current Limit

DS009063-38

Adjustment Current

DS009063-39

Dropout Voltage

DS009063-40

Temperature Stability

DS009063-41

Minimum Operating Current

DS009063-42

Ripple Rejection

DS009063-43

Ripple Rejection

DS009063-44

Ripple Rejection

DS009063-45

Output Impedance

DS009063-46

Line Transient Response

DS009063-47

Load Transient Response

DS009063-48

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Application HintsIn operation, the LM117 develops a nominal 1.25V referencevoltage, VREF, between the output and adjustment terminal.The reference voltage is impressed across program resistorR1 and, since the voltage is constant, a constant current I1then flows through the output set resistor R2, giving an out-put voltage of

Since the 100 µA current from the adjustment terminal repre-sents an error term, the LM117 was designed to minimizeIADJ and make it very constant with line and load changes.To do this, all quiescent operating current is returned to theoutput establishing a minimum load current requirement. Ifthere is insufficient load on the output, the output will rise.

External Capacitors

An input bypass capacitor is recommended. A 0.1 µF disc or1 µF solid tantalum on the input is suitable input bypassingfor almost all applications. The device is more sensitive tothe absence of input bypassing when adjustment or outputcapacitors are used but the above values will eliminate thepossibility of problems.

The adjustment terminal can be bypassed to ground on theLM117 to improve ripple rejection. This bypass capacitorprevents ripple from being amplified as the output voltage isincreased. With a 10 µF bypass capacitor 80 dB ripple rejec-tion is obtainable at any output level. Increases over 10 µFdo not appreciably improve the ripple rejection at frequen-cies above 120 Hz. If the bypass capacitor is used, it issometimes necessary to include protection diodes to preventthe capacitor from discharging through internal low currentpaths and damaging the device.

In general, the best type of capacitors to use is solid tanta-lum. Solid tantalum capacitors have low impedance even athigh frequencies. Depending upon capacitor construction, ittakes about 25 µF in aluminum electrolytic to equal 1 µFsolid tantalum at high frequencies. Ceramic capacitors arealso good at high frequencies; but some types have a largedecrease in capacitance at frequencies around 0.5 MHz. Forthis reason, 0.01 µF disc may seem to work better than a 0.1µF disc as a bypass.

Although the LM117 is stable with no output capacitors, likeany feedback circuit, certain values of external capacitancecan cause excessive ringing. This occurs with values be-tween 500 pF and 5000 pF. A 1 µF solid tantalum (or 25 µF

aluminum electrolytic) on the output swamps this effect andinsures stability. Any increase of the load capacitance largerthan 10 µF will merely improve the loop stability and outputimpedance.

Load Regulation

The LM117 is capable of providing extremely good loadregulation but a few precautions are needed to obtain maxi-mum performance. The current set resistor connected be-tween the adjustment terminal and the output terminal (usu-ally 240Ω) should be tied directly to the output (case) of theregulator rather than near the load. This eliminates linedrops from appearing effectively in series with the referenceand degrading regulation. For example, a 15V regulator with0.05Ω resistance between the regulator and load will have aload regulation due to line resistance of 0.05Ω x IL. If the setresistor is connected near the load the effective line resis-tance will be 0.05Ω (1 + R2/R1) or in this case, 11.5 timesworse.

Figure 2 shows the effect of resistance between the regula-tor and 240Ω set resistor.

With the TO-3 package, it is easy to minimize the resistancefrom the case to the set resistor, by using two separate leadsto the case. However, with the TO-39 package, care shouldbe taken to minimize the wire length of the output lead. Theground of R2 can be returned near the ground of the load toprovide remote ground sensing and improve load regulation.

Protection Diodes

When external capacitors are used with any IC regulator it issometimes necessary to add protection diodes to preventthe capacitors from discharging through low current pointsinto the regulator. Most 10 µF capacitors have low enoughinternal series resistance to deliver 20A spikes whenshorted. Although the surge is short, there is enough energyto damage parts of the IC.

When an output capacitor is connected to a regulator andthe input is shorted, the output capacitor will discharge intothe output of the regulator. The discharge current dependson the value of the capacitor, the output voltage of the regu-lator, and the rate of decrease of VIN. In the LM117, this dis-charge path is through a large junction that is able to sustain15A surge with no problem. This is not true of other types ofpositive regulators. For output capacitors of 25 µF or less,there is no need to use diodes.

The bypass capacitor on the adjustment terminal can dis-charge through a low current junction. Discharge occurswhen either the input or output is shorted. Internal to theLM117 is a 50Ω resistor which limits the peak discharge cur-rent. No protection is needed for output voltages of 25V or

DS009063-5

FIGURE 1.

DS009063-6

FIGURE 2. Regulator with Line Resistance in OutputLead

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Application Hints (Continued)

less and 10 µF capacitance. Figure 3 shows an LM117 withprotection diodes included for use with outputs greater than25V and high values of output capacitance.

When a value for θ(H−A) is found using the equation shown,a heatsink must be selected that has a value that is less thanor equal to this number.

θ(H−A) is specified numerically by the heatsink manufacturerin the catalog, or shown in a curve that plots temperature risevs power dissipation for the heatsink.

HEATSINKING TO-263 AND SOT-223 PACKAGE PARTS

Both the TO-263 (“S”) and SOT-223 (“MP”) packages use acopper plane on the PCB and the PCB itself as a heatsink.To optimize the heat sinking ability of the plane and PCB,solder the tab of the package to the plane.

Figure 4 shows for the TO-263 the measured values of θ(J−A)

for different copper area sizes using a typical PCB with 1ounce copper and no solder mask over the copper area usedfor heatsinking.

As shown in the figure, increasing the copper area beyond 1square inch produces very little improvement. It should alsobe observed that the minimum value of θ(J−A) for the TO-263package mounted to a PCB is 32˚C/W.

As a design aid, Figure 5 shows the maximum allowablepower dissipation compared to ambient temperature for theTO-263 device (assuming θ(J−A) is 35˚C/W and the maxi-mum junction temperature is 125˚C).

Figure 6 and Figure 7 show the information for the SOT-223package. Figure 7 assumes a θ(J−A) of 74˚C/W for 1 ouncecopper and 51˚C/W for 2 ounce copper and a maximumjunction temperature of 125˚C.

DS009063-7

D1 protects against C1D2 protects against C2

FIGURE 3. Regulator with Protection Diodes

DS009063-55

FIGURE 4. θ(J−A) vs Copper (1 ounce) Area for theTO-263 Package

DS009063-56

FIGURE 5. Maximum Power Dissipation vs T AMB forthe TO-263 Package

DS009063-57

FIGURE 6. θ(J−A) vs Copper (2 ounce) Area for theSOT-223 Package

DS009063-58

FIGURE 7. Maximum Power Dissipation vs T AMB forthe SOT-223 Package

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Please see AN1028 for power enhancement techniques tobe used with the SOT-223 package.

Schematic Diagram

Typical ApplicationsDS009063-8

5V Logic Regulator with Electronic Shutdown *

DS009063-3

*Min. output ≈ 1.2V

Slow Turn-On 15V Regulator

DS009063-9

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Typical Applications (Continued)

Adjustable Regulator with Improved Ripple Rejection

DS009063-10

†Solid tantalum*Discharges C1 if output is shorted to ground

High Stability 10V Regulator

DS009063-11

High Current Adjustable Regulator

DS009063-12

‡Optional—improves ripple rejection†Solid tantalum*Minimum load current = 30 mA

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0 to 30V Regulator

DS009063-13

Full output current not available at high input-output voltages

Power Follower

DS009063-14

5A Constant Voltage/Constant Current Regulator

DS009063-15

†Solid tantalum*Lights in constant current mode

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1A Current Regulator

DS009063-16

1.2V–20V Regulator with MinimumProgram Current

DS009063-17

*Minimum load current ≈ 4 mA

High Gain Amplifier

DS009063-18

Low Cost 3A Switching Regulator

DS009063-19

†Solid tantalum*Core—Arnold A-254168-2 60 turns

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4A Switching Regulator with Overload Protection

DS009063-20

†Solid tantalum*Core—Arnold A-254168-2 60 turns

Precision Current Limiter

DS009063-21

Tracking Preregulator

DS009063-22

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Current Limited Voltage Regulator

DS009063-23

(Compared to LM117’s higher current limit)—At 50 mA output only 3⁄4 volt of drop occurs in R3 and R4

Adjusting Multiple On-Card Regulators with Single Control *

DS009063-24

*All outputs within ±100 mV†Minimum load—10 mA

AC Voltage Regulator

DS009063-25

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12V Battery Charger

DS009063-26

Use of RS allows low charging rates with fully charged battery.

50 mA Constant Current Battery Charger

DS009063-27

Adjustable 4A Regulator

DS009063-28

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Current Limited 6V Charger

DS009063-29

*Sets peak current (0.6A for 1Ω)**The 1000 µF is recommended to filter out input transients

Digitally Selected Outputs

DS009063-2

*Sets maximum VOUT

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Connection Diagrams

(TO-3)Metal Can Package

DS009063-30

CASE IS OUTPUT

Bottom ViewSteel Package

Order Number LM117K STEELor LM317K STEEL

See NS Package Number K02AOrder Number LM117K/883

See NS Package Number K02C

(TO-39)Metal Can Package

DS009063-31

CASE IS OUTPUT

Bottom ViewOrder Number LM117H,

LM117H/883,LM317AH or LM317H

See NS Package Number H03A

(TO-220)Plastic Package

DS009063-32

Front ViewOrder Number LM317AT or LM317T

See NS Package Number T03B

(TO-263) Surface-Mount Package

DS009063-35

Top View

DS009063-36

Side ViewOrder Number LM317AS or LM317S

See NS Package Number TS3B

Ceramic LeadlessChip Carrier

DS009063-34

Top ViewOrder Number LM117E/883

See NS Package Number E20A

3-Lead SOT-223

DS009063-59

Front ViewOrder Part Number LM317EMP

Package Marked N01ASee NSC Package Number MA04A

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16

Physical Dimensions inches (millimeters) unless otherwise noted

Ceramic Leadless Chip CarrierOrder Number LM117E/883NS Package Number E20A

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Physical Dimensions inches (millimeters) unless otherwise noted (Continued)

(TO-39) Metal Can PackageOrder Number LM117H, LM117H/883, LM317AH or LM317H

NS Package Number H03A

TO-3 Metal Can Package (K)Order Number LM117K STEEL,

LM117K STEEL/883, or LM317K STEELNS Package Number K02A

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TO-3 Metal Can Package (K)Mil-Aero Product

Order Number LM117K/883NS Package Number K02C

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3-Lead SOT-223 PackageOrder Number LM317EMP

NS Package Number MA04A

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(TO-220) Outline DrawingOrder Number LM317AT or LM317T

NS Package Number T03B

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LIFE SUPPORT POLICY

NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DE-VICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF NATIONAL SEMI-CONDUCTOR CORPORATION. As used herein:1. Life support devices or systems are devices or sys-

tems which, (a) are intended for surgical implant intothe body, or (b) support or sustain life, and whose fail-ure to perform when properly used in accordancewith instructions for use provided in the labeling, canbe reasonably expected to result in a significant injuryto the user.

2. A critical component in any component of a life supportdevice or system whose failure to perform can be rea-sonably expected to cause the failure of the life supportdevice or system, or to affect its safety or effectiveness.

National SemiconductorCorporationAmericasTel: 1-800-272-9959Fax: 1-800-737-7018Email: [email protected]

www.national.com

National SemiconductorEurope

Fax: +49 (0) 1 80-530 85 86Email: [email protected]

Deutsch Tel: +49 (0) 1 80-530 85 85English Tel: +49 (0) 1 80-532 78 32Français Tel: +49 (0) 1 80-532 93 58Italiano Tel: +49 (0) 1 80-534 16 80

National SemiconductorAsia Pacific CustomerResponse GroupTel: 65-2544466Fax: 65-2504466Email: [email protected]

National SemiconductorJapan Ltd.Tel: 81-3-5620-6175Fax: 81-3-5620-6179

Order Number LM317AS or LM317SNS Package Number TS3B

LM11

7/LM

317A

/LM

317

3-Te

rmin

alA

djus

tabl

eR

egul

ator

National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications.

LM134/LM234/LM3343-Terminal Adjustable Current SourcesGeneral DescriptionThe LM134/LM234/LM334 are 3-terminal adjustable currentsources featuring 10,000:1 range in operating current, excel-lent current regulation and a wide dynamic voltage range of1V to 40V. Current is established with one external resistorand no other parts are required. Initial current accuracy is±3%. The LM134/LM234/LM334 are true floating currentsources with no separate power supply connections. In ad-dition, reverse applied voltages of up to 20V will draw only afew dozen microamperes of current, allowing the devices toact as both a rectifier and current source in AC applications.

The sense voltage used to establish operating current in theLM134 is 64mV at 25˚C and is directly proportional to abso-lute temperature (˚K). The simplest one external resistorconnection, then, generates a current with ≈+0.33%/˚C tem-perature dependence. Zero drift operation can be obtainedby 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 andLM234-6 are specified as true temperature sensors withguaranteed initial accuracy of ±3˚C and ±6˚C, respectively.These devices are ideal in remote sense applications be-cause series resistance in long wire runs does not affectaccuracy. 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 theLM334 from 0˚C to +70˚C. These devices are available inTO-46 hermetic, TO-92 and SO-8 plastic packages.

Featuresn Operates from 1V to 40Vn 0.02%/V current regulationn Programmable from 1µA to 10mAn True 2-terminal operationn Available as fully specified temperature sensorn ±3% initial accuracy

Connection Diagrams

SO-8Surface Mount Package

SO-8 Alternative PinoutSurface Mount Package

00569724

Order Number LM334M or LM334MXSee NS Package Number M08A

00569725

Order Number LM334SM or LM334SMXSee NS Package Number M08A

TO-46Metal Can Package TO-92 Plastic Package

00569712

V− Pin is electrically connected to case.

Bottom ViewOrder Number LM134H,

LM234H or LM334HSee NS Package

Number H03H

00569710

Bottom ViewOrder Number LM334Z, LM234Z-3 or LM234Z-6

See NS Package Number Z03A

March 2005LM

134/LM234/LM

3343-Term

inalAdjustable

Current

Sources

© 2005 National Semiconductor Corporation DS005697 www.national.com

Absolute Maximum Ratings (Note 1)

If Military/Aerospace specified devices are required,please contact the National Semiconductor Sales Office/Distributors for availability and specifications.

V+ to V− Forward Voltage

LM134/LM234/LM334 40V

LM234-3/LM234-6 30V

V+ to V− Reverse Voltage 20V

R Pin to V− Voltage 5V

Set Current 10 mA

Power Dissipation 400 mW

ESD Susceptibility (Note 6) 2000V

Operating Temperature Range (Note5)

LM134 −55˚C to +125˚C

LM234/LM234-3/LM234-6 −25˚C to +100˚C

LM334 0˚C to +70˚C

Soldering Information

TO-92 Package (10 sec.) 260˚C

TO-46 Package (10 sec.) 300˚C

SO Package

Vapor Phase (60 sec.) 215˚C

Infrared (15 sec.) 220˚C

See AN-450 “Surface Mounting Methods and Their Effect onProduct Reliability” (Appendix D) for other methods of sol-dering surface mount devices.

Electrical Characteristics (Note 2)

Parameter Conditions LM134/LM234 LM334 Units


Set Current Error, V+=2.5V, 10µA ≤ ISET ≤ 1mA 3 6 %

(Note 3) 1mA < ISET ≤ 5mA 5 8 %

2µA ≤ ISET < 10µA 8 12 %

Ratio of Set Current to 100µA ≤ ISET ≤ 1mA 14 18 23 14 18 26

Bias Current 1mA ≤ ISET ≤ 5mA 14 14

2 µA≤ISET≤100 µA 18 23 18 26

Minimum Operating Voltage 2µA ≤ ISET ≤ 100µA 0.8 0.8 V

100µA < ISET ≤ 1mA 0.9 0.9 V

1mA < ISET ≤ 5mA 1.0 1.0 V

Average Change in Set Current 2µA ≤ ISET ≤ 1mA

with Input Voltage 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

1mA < ISET ≤ 5mA

1.5V ≤ V ≤ 5V 0.03 0.03 %/V

5V ≤ V ≤ 40V 0.02 0.02 %/V

Temperature Dependence of 25µA ≤ ISET ≤ 1mA 0.96T T 1.04T 0.96T T 1.04T

Set Current (Note 4)

Effective Shunt Capacitance 15 15 pF

Note 1: .“Absolute Maximum Ratings” indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device isfunctional, but do not guarantee specific performance limits.

Note 2: Unless otherwise specified, tests are performed at Tj = 25˚C with pulse testing so that junction temperature does not change during test

Note 3: Set current is the current flowing into the V+ pin. For the Basic 2-Terminal Current Source circuit shown on the first page of this data sheet. ISET isdetermined by the following formula: ISET = 67.7 mV/RSET (@ 25˚C). Set current error is expressed as a percent deviation from this amount. ISET increases at0.336%/˚C @ Tj = 25˚C (227 µV/˚C).

LM13

4/LM

234/

LM33

4

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Electrical Characteristics (Note 2) (Continued)Note 4: ISET is directly proportional to absolute temperature (˚K). ISET at any temperature can be calculated from: ISET = Io (T/To) where Io is ISET measured at To(˚K).

Note 5: For elevated temperature operation, TJ max is:

LM134 150˚C

LM234 125˚C

LM334 100˚C

Thermal Resistance TO-92 TO-46 SO-8

θja (Junction toAmbient)

180˚C/W (0.4" leads) 440˚C/W 165˚C/W

160˚C/W (0.125"leads)

θjc (Junction to Case) N/A 32˚C/W 80˚C/W

Note 6: Human body model, 100pF discharged through a 1.5kΩ resistor.

Electrical Characteristics (Note 2)

Parameter Conditions LM234-3 LM234-6 Units


Set Current Error, V+=2.5V, 100µA ≤ ISET ≤ 1mA ±1 ±2 %

(Note 3) TJ = 25˚

Equivalent Temperature Error ±3 ±6 ˚C

Ratio of Set Current to 100µA ≤ ISET ≤ 1mA 14 18 26 14 18 26

Bias Current

Minimum Operating Voltage 100µA ISET ≤ 1mA 0.9 0.9 V

Average Change in Set Current 100µA ≤ ISET ≤ 1mA

with Input Voltage 1.5 ≤ V+ ≤ 5V 0.02 0.05 0.02 0.01 %/V

5V ≤ V+ ≤ 30V 0.01 0.03 0.01 0.05 %/V

Temperature Dependence of 100µA ≤ ISET ≤ 1mA 0.98T T 1.02T 0.97T T 1.03T

Set Current (Note 4) and

Equivalent Slope Error ±2 ±3 %

Effective Shunt Capacitance 15 15 pF

LM134/LM

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Typical Performance Characteristics

Output ImpedanceMaximum Slew Rate

Linear Operation

00569730 00569731

Start-Up Transient Response

00569732 00569733

Voltage Across RSET (VR) Current Noise

00569734 00569735

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Typical Performance Characteristics (Continued)

Turn-On Voltage Ratio of ISET to IBIAS

00569729 00569703

Application HintsThe LM134 has been designed for ease of application, but ageneral discussion of design features is presented here tofamiliarize the designer with device characteristics whichmay not be immediately obvious. These include the effectsof slewing, power dissipation, capacitance, noise, and con-tact resistance.

CALCULATING RSET

The total current through the LM134 (ISET) is the sum of thecurrent going through the SET resistor (IR) and the LM134’sbias current (IBIAS), as shown in Figure 1.

A graph showing the ratio of these two currents is suppliedunder Ratio of ISET to IBIAS in the Typical PerformanceCharacteristics section. The current flowing through RSET isdetermined by VR, which is approximately 214µV/˚K (64mV/298˚K ∼ 214µV/˚K).

Since (for a given set current) IBIAS is simply a percentage ofISET, the equation can be rewritten

where n is the ratio of ISET to IBIAS as specified in theElectrical Characteristics Section and shown in the graph.Since n is typically 18 for 2µA ≤ ISET ≤ 1mA, the equation canbe further simplified to

for most set currents.

SLEW RATE

At slew rates above a given threshold (see curve), theLM134 may exhibit non-linear current shifts. The slewingrate at which this occurs is directly proportional to ISET. AtISET = 10µA, maximum dV/dt is 0.01V/µs; at ISET = 1mA, thelimit is 1V/µs. Slew rates above the limit do not harm theLM134, or cause large currents to flow.

THERMAL EFFECTS

Internal heating can have a significant effect on currentregulation for ISET greater than 100µA. For example, each1V increase across the LM134 at ISET = 1 mA will increasejunction temperature by ≈0.4˚C in still air. Output current(ISET) has a temperature coefficient of ≈0.33%/˚C, so thechange in current due to temperature rise will be (0.4)(0.33) = 0.132%. This is a 10:1 degradation in regulationcompared to true electrical effects. Thermal effects, there-fore, must be taken into account when DC regulation iscritical and ISET exceeds 100µA. Heat sinking of the TO-46package or the TO-92 leads can reduce this effect by morethan 3:1.

SHUNT CAPACITANCE

In certain applications, the 15 pF shunt capacitance of theLM134 may have to be reduced, either because of loadingproblems or because it limits the AC output impedance of thecurrent source. This can be easily accomplished by bufferingthe LM134 with an FET as shown in the applications. Thiscan reduce capacitance to less than 3 pF and improve

00569727

FIGURE 1. Basic Current Source

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regulation by at least an order of magnitude. DC character-istics (with the exception of minimum input voltage), are notaffected.

NOISE

Current noise generated by the LM134 is approximately 4times the shot noise of a transistor. If the LM134 is used asan active load for a transistor amplifier, input referred noisewill be increased by about 12dB. In many cases, this isacceptable and a single stage amplifier can be built with avoltage gain exceeding 2000.

LEAD RESISTANCE

The sense voltage which determines operating current of theLM134 is less than 100mV. At this level, thermocouple orlead resistance effects should be minimized by locating thecurrent setting resistor physically close to the device. Sock-ets should be avoided if possible. It takes only 0.7Ω contactresistance to reduce output current by 1% at the 1 mA level.

SENSING TEMPERATURE

The LM134 makes an ideal remote temperature sensor be-cause its current mode operation does not lose accuracyover long wire runs. Output current is directly proportional toabsolute temperature in degrees Kelvin, according to thefollowing formula:

Calibration of the LM134 is greatly simplified because of thefact that most of the initial inaccuracy is due to a gain term(slope error) and not an offset. This means that a calibrationconsisting of a gain adjustment only will trim both slope andzero at the same time. In addition, gain adjustment is a onepoint trim because the output of the LM134 extrapolates tozero at 0˚K, independent of RSET or any initial inaccuracy.

This property of the LM134 is illustrated in the accompanyinggraph. Line abc is the sensor current before trimming. Linea'b'c' is the desired output. A gain trim done at T2 will movethe output from b to b' and will simultaneously correct theslope so that the output at T1 and T3 will be correct. Thisgain trim can be done on RSET or on the load resistor usedto terminate the LM134. Slope error after trim will normallybe less than ±1%. To maintain this accuracy, however, a lowtemperature coefficient resistor must be used for RSET.

A 33 ppm/˚C drift of RSET will give a 1% slope error becausethe resistor will normally see about the same temperaturevariations as the LM134. Separating RSET from the LM134requires 3 wires and has lead resistance problems, so is not

normally recommended. Metal film resistors with less than20 ppm/˚C drift are readily available. Wire wound resistorsmay also be used where best stability is required.

APPLICATION AS A ZERO TEMPERATURECOEFFICENT CURRENT SOURCE

Adding a diode and a resistor to the standard LM134 con-figuration can cancel the temperature-dependent character-istic of the LM134. The circuit shown in Figure 3 balancesthe positive tempco of the LM134 (about +0.23 mV/˚C) withthe negative tempco of a forward-biased silicon diode (about−2.5 mV/˚C).

00569704

FIGURE 2. Gain Adjustment

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The set current (ISET) is the sum of I1 and I2, each contrib-uting approximately 50% of the set current, and IBIAS. IBIAS isusually included in the I1 term by increasing the VR valueused for calculations by 5.9%. (See CALCULATING RSET.)

The first step is to minimize the tempco of the circuit, usingthe following equations. An example is given using a value of+227µV/˚C as the tempco of the LM134 (which includes theIBIAS component), and −2.5 mV/˚C as the tempco of thediode (for best results, this value should be directly mea-sured or obtained from the manufacturer of the diode).

With the R1 to R2 ratio determined, values for R1 and R2

should be determined to give the desired set current. Theformula for calculating the set current at T = 25˚C is shownbelow, followed by an example that assumes the forwardvoltage drop across the diode (VD) is 0.6V, the voltageacross R1 is 67.7mV (64 mV + 5.9% to account for IBIAS),and R2/R1 = 10 (from the previous calculations).

This circuit will eliminate most of the LM134’s temperaturecoefficient, and it does a good job even if the estimates of thediode’s characteristics are not accurate (as the followingexample will show). For lowest tempco with a specific diodeat the desired ISET, however, the circuit should be built andtested over temperature. If the measured tempco of ISET ispositive, R2 should be reduced. If the resulting tempco isnegative, R2 should be increased. The recommended diodefor use in this circuit is the 1N457 because its tempco iscentered at 11 times the tempco of the LM134, allowing R2 =10 R1. You can also use this circuit to create a current sourcewith non-zero tempcos by setting the tempco component ofthe tempco equation to the desired value instead of 0.

EXAMPLE: A 1mA, Zero-Tempco Current Source

First, solve for R1 and R2:

The values of R1 and R2 can be changed to standard 1%resistor values (R1 = 133Ω and R2 = 1.33kΩ) with less thana 0.75% error.

00569728

FIGURE 3. Zero Tempco Current Source

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If the forward voltage drop of the diode was 0.65V instead ofthe estimate of 0.6V (an error of 8%), the actual set currentwill be

an error of less than 5%.

If the estimate for the tempco of the diode’s forward voltagedrop was off, the tempco cancellation is still reasonablyeffective. Assume the tempco of the diode is 2.6mV/˚C in-stead of 2.5mV/˚C (an error of 4%). The tempco of the circuitis now:

A 1mA LM134 current source with no temperature compen-sation would have a set resistor of 68Ω and a resultingtempco of

So even if the diode’s tempco varies as much as ±4% fromits estimated value, the circuit still eliminates 98% of theLM134’s inherent tempco.

Typical ApplicationsGround Referred Fahrenheit Thermometer

00569715

*Select R3 = VREF/583µA. VREF may be any stable positive voltage ≥ 2V

Trim R3 to calibrate

Terminating Remote Sensor for Voltage Output

00569714

Low Output Impedance Thermometer

00569706

*Output impedance of the LM134 at the “R” pin is approximately

where R2 is the equivalent external resistance connected from the V− pinto ground. This negative resistance can be reduced by a factor of 5 ormore by inserting an equivalent resistor R3 = (R2/16) in series with theoutput.

Low Output Impedance Thermometer

00569716

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Higher Output Current

00569705

*Select R1 and C1 for optimum stability

Basic 2-Terminal Current Source

00569701

Micropower Bias Low Input Voltage Reference Driver

00569717

00569718

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Ramp Generator

00569719

1.2V Reference Operates on 10 µA and 2V

00569720

*Select ratio of R1 to R2 to obtain zero temperature drift

1.2V Regulator with 1.8V Minimum Input

00569707

*Select ratio of R1 to R2 for zero temperature drift

Zener Biasing

00569749

Alternate Trimming Technique

00569750

*For ±10% adjustment, select RSET10% high, and make R1 ≈ 3 RSET

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Buffer for Photoconductive Cell

00569751

Generating Negative Output Impedance

00569723

*ZOUT ≈ −16 • R1 (R1/VIN must not exceed ISET)

In-Line Current Limiter

00569709

*Use minimum value required to ensure stability of protected device. Thisminimizes inrush current to a direct short.

Schematic Diagram

FET Cascoding for Low Capacitance and/or Ultra High Output Impedance

00569721

*Select Q1 or Q2 to ensure at least 1V across the LM134. Vp (1 −ISET/IDSS) ≥ 1.2V. 00569722

FIGURE 4.

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Schematic Diagram (Continued)

00569711

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Physical Dimensions inches (millimeters)unless otherwise noted

Order Number LM134H, LM234H or LM334HNS Package Number H03H

SO Package (M)Order Number LM334M, LM334MX,

LM334SM or LM334SMXNS Package Number M08A

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Order Number LM334Z, LM234Z-3 or LM234Z-6NS Package Number Z03A

National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reservesthe right at any time without notice to change said circuitry and specifications.

For the most current product information visit us at www.national.com.

LIFE SUPPORT POLICY

NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMSWITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL COUNSEL OF NATIONAL SEMICONDUCTORCORPORATION. As used herein:

1. Life support devices or systems are devices or systemswhich, (a) are intended for surgical implant into the body, or(b) support or sustain life, and whose failure to perform whenproperly used in accordance with instructions for useprovided in the labeling, can be reasonably expected to resultin a significant injury to the user.

2. A critical component is any component of a life supportdevice or system whose failure to perform can be reasonablyexpected to cause the failure of the life support device orsystem, or to affect its safety or effectiveness.

BANNED SUBSTANCE COMPLIANCE

National Semiconductor manufactures products and uses packing materials that meet the provisions of the Customer ProductsStewardship Specification (CSP-9-111C2) and the Banned Substances and Materials of Interest Specification (CSP-9-111S2) and containno ‘‘Banned Substances’’ as defined in CSP-9-111S2.

National SemiconductorAmericas CustomerSupport CenterEmail: [email protected]: 1-800-272-9959

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Fax: +49 (0) 180-530 85 86Email: [email protected]

Deutsch Tel: +49 (0) 69 9508 6208English Tel: +44 (0) 870 24 0 2171Français Tel: +33 (0) 1 41 91 8790

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National SemiconductorJapan Customer Support CenterFax: 81-3-5639-7507Email: [email protected]: 81-3-5639-7560

www.national.com

LM13

4/LM

234/

LM33

43-

Term

inal

Adj

usta

ble

Cur

rent

Sou

rces

1. For a smaller package size and more values, see TTWB Series.2. 500 V isolation.3. Operating temperature range −40° C to +85° C.4. Electrical specifications at 25° C.

WideBandRFTransformers

Document 116-1

SPECIFICATIONS

Coilcraft wide band transformers provide reliable per-formance at a price considerably lower than currentlyavailable equivalents.

The transformers are offered in tapped or untapped con-figurations and are packaged in a low-profile DIP-styleplastic case. All parts are available in either a surfacemount version or a through-hole version that’s compat-ible with standard DIP sockets. (For a smaller packagesize and more values, see our TTWB Series.)

Applications include impedance matching, voltage orcurrent transformation, DC isolation, balanced/unbal-anced mixing, matching, power splitting, coupling, andsignal inversion.

Custom wide band transformers with special combina-tions of impedance ratio, insertion loss, frequency re-sponse, and current handling are also available.

Pins 1-3 Pins 6-4Part Number 1Part Number1 Ω IDC Max Frequency L Min DCR Max L Min DCR Max

Configuration (Through-Hole) (Surface Mount) Ratio (mA) (MHz) (H) (Ohms) (H) (Ohms)

WB1010-PC WB1010-SM 1:1 250 .005-100 780 .320 780 .320WB1010-1-PC WB1010-1-SM 1:1 250 .04-175 95 .200 95 .200WB1015-PC WB1015-SM 1:1.5 250 .1-150 80 .145 51 .130WB1040-PC WB1040-SM 1:4 250 .2-300 95 .160 25 .115

WB2010-PC WB2010-SM 1:1 250 .005-100 780 .320 780 .320WB2010-1-PC WB2010-1-SM 1:1 250 .04-175 95 .200 95 .200WB2040-PC WB2040-SM 1:4 250 .2-300 95 .160 25 .115

WB3010-PC WB3010-SM 1:1 250 .005-100 780 .320 780 .320WB3010-1-PC WB3010-1-SM 1:1 250 .04-175 95 .200 95 .200WB3015-PC WB3015-SM 1:1.5 250 .1-150 80 .145 51 .130WB3040-PC WB3040-SM 1:4 250 .2-300 95 .160 25 .115

Specifications subject to change without notice. Document 116-1 Revised 01/29/01

www.DataSheet4U.comwww.DataSheet4U.com

( DataSheet : www.DataSheet4U.com )

WideBandRFTransformersDIMENSIONS ATTENUATIONVSCURRENT(TYP.)

TYPICALFREQUENCYRESPONSE

Document 116-2

Specifications subject to change without notice. Document 116-2 Revised 1/29/99

Documents

Proyecto Fin de Carrerabibing.us.es/proyectos/abreproy/11385/descargar_fichero/1%2F10_Anexo.pdf · series (3A) and LM138 series (5A) data sheets. For the negative complement, see