Datasheet LM334Z, LM334D, LM334, LM234Z, LM234 Datasheet (SGS Thomson Microelectronics)

THREETERMINAL ADJUSTABLECURRENT SOURCES

.OPERATESfrom1V to 40V

.0.02%V CURRENT REGULATION

.PROGRAMMABLEfrom1µAto10mA

.±3% INITIALACCURACY

DESC RIP TI ON

The LM134/LM234/LM334 are 3-terminal adjust­able currentsourcescharacterizedby :

-an operatingcurrent rangeof 10000 : 1

-an excellentcurrentregulation

-a widedynamicvoltage range of 1V to 40V

The current is determined by an external resistor
withoutrequiringother externalcomponents.

Reversevoltagesof up to 20V will only draw a cur­rent of several microamperes. This enables the
circuittooperateasa rectifierandasasourceofcur­rentin a.c. applications.

For the LM134/LM234/LM334,the voltage on the
controlpin is 64mV at+25
tionaltotheabsolutetemperature(
external resistor connection generates a current
with ≈ 0.33%/

o

C temperature dependence. Zero
driftcanbeobtainedbyaddinganadditionalresistor
and a diode to theexternalcircuit.

o

C and is directlypropor-

o

K).Thesimplest

LM134-LM234

(Plastic Package)

(PlasticMicropackage)

ORDER CODES

Part Num-

ber

LM134 –55
LM234 –25
LM334 0

Example : LM134Z

LM334

Z

TO92

D

SO8

Temperature

Range

o

C, +125oC ••

o

C, +100oC ••

o

C, +70oC ••

Package

ZD

PIN CONNECTIO N S

TO92

(Bottomview)

ADJ

-

V

3

+

V

21

October1997 1/10

SO8

(Topview)

NC NC

8765

1234

ADJ NC NC

-

V NC

+

V

LM134-LM234-LM334

SCHEMA TIC DIAG RAM

Q3

V

Q4 Q5 Q6

C1

Q1

Q2

50pF

ADJ

V

ABSOLUTE MAXIMUM RATING

Symbol Parameter LM134 - LM234 LM334 Unit

Voltage V

-

V

ADJ

I

SET

P

T

T

ADJ Pin to V–Voltage 5 5 V
Set Current 10 10 mA
Power Dissipation 400 400 mW

tot

Storage Temperature Range –65 to +150

stg

Operating Free-air Temperature Range LM134

oper

Forward
Reverse

+

to V

–

LM234
LM334

40
20

–55 to +125
–25 to +100

0 to +70

30
20

V

o

C

o

C

2/10

LM134-LM234-LM334

ELECTRICAL CHARACTERISTICS

= +25oC with pulsetesting so that junction temperature does not change during testing

T

j

(unless otherwise specified)

Parameter

+

Set Current Error (V

10µA ≤ I
1mA ≤ I
2µA ≤ I

SET

SET

SET

Ratio of Set Current to V

10µA ≤ I
1mA ≤ I
2µA ≤ I

SET

SET

SET

= +2.5V) - (note 1)

≤ 1mA

≤ 5mA

≤ 10µA

≤ 1mA

≤ 5mA

≤ 10µA

–

Current

Minimum Operating Voltage

SET

SET

SET

≤ 100µA

≤ 1mA

≤ 5mA

2µA ≤ I
100µA ≤ I
1mA ≤ I

Average change in set current with input voltage

2µA ≤ I

1mA ≤ I

≤ 1mA

SET

+1.5V ≤ V
+5V ≤ V

≤ 5mA

SET

+1.5V ≤ V
+5V ≤ V

+

+

≤ +40V

+

+

≤ +40V

≤ +5V

+ ≤ +5V

Temperature Dependence of set current - (note 2)

25µA ≤ I

≤ 1mA 0.96 T T 1.04 T 0.96 T T 1.04 T

SET

Effective Shunt Capacitance 15 15 pF

Notes : 1. Set current is the current flowing into theV+pin. It is determined by the following formula Iset = 67.7mV/R

(Tj=+25oC).
Set current error is expressed as a percent deviation from this amount.

is directly proportional to absolute temperature (oK). I

2. I

set

I

(T/TO) where IOis Iset measured at TO(oK).

set=IO

LM134 - LM234 LM334

Min. Typ. Max. Min. Typ. Max.

14 18

14
14

0.8

0.9

0.02

0.01

0.03

0.02

at any temperature can be calculated from

set

3
5
8

23 14 18

14
14

0.8

0.9

1

0.05

0.03

1

0.02

0.01

0.03

0.02

6
8

12

26

0.1

0.05

set

Unit

%

V

%/V

3/10

LM134-LM234-LM334

4/10

LM134-LM234-LM334

APPL ICATION HINT

SLEWRATE
At slew rates above a threshold (see curve) the

LM134,LM234, LM334can havea non-linearcur­rentcharacteristic.Theslewrateatwhich thistakes
place is directly proportionalto I
dv/dt max. =0.01V/µS ; atI

set

set

.AtI

=10µA,

set

=1mA,dv/dtmax.=
1V/µS.Slew ratesof more than1V/µSdonotdam-
age the circuitnor do they producehigh currents.

THERMAL EFFECTS
Internalheatingcanhavea significanteffecton cur-

rent regulationfor an I

above100µA. For exam-

set

ple, each increase of 1V in the voltage across the
LM134at I
peratureby ≈ 0.4
(I

) has a temperature coefficient of about

set

0.33%/

= 1mA will increase the junctiontem-

set

o

C(in stillair). Theoutput current

o

C. Thusthe changein currentdue tothe in­creasein temperaturewill be (0.4)(0.33)=0.132%.
This is a degradationof 10 : 1 in regulationversus
the trueelectricaleffects.Thermaleffectsshouldbe
taken into account when d.c. regulation is critical
and I

ishigherthan100µA. The dissipationof the

set

connectionsof CB-97packagecanreducethisther­mal effectby acoefficientof more than 3.

SHUNTCAPACITANCE
In certainapplications,the15pFvaluefor theshunt

capacitanceshouldbe reduced :

- becauseofloadingproblems,

- becauseof limitation of the outputimpedance of
the currentsource in a.c. applications.This reduc­tion of the capacitancecan be easily carried outby
addingaFETasindicatedinthetypicalapplications.
The valueof thiscapacitancecanbe reduced by at
least3pFandregulationcan be improved by an or­derofmagnitudewithoutanymodificationofthed.c.
characteristics(except for the minimum input volt­age).

NOISE
The current noise produced by LM134, LM234,

LM334 is about 4 times that of a transistor. If the
LM134, LM234,LM334 is utilizedas anactive load
for a transistoramplifier, the noise at the input will
increase by about 12dB. In most cases this is ac­ceptable,and a single amplifier can be built with a
voltagegain higher than 2000.

LEAD RESISTANCE
The sense voltagewhich determinesthe currentof

the LM134,LM234,LM334, is less than 100mV.At
this level, the effects of the thermocoupleand the

connectionresistanceshould be reduced by locat­ing the current setting resistor close to the device.
Donot usesocketsfortheICs. A contactresistance
of 0.7Ω is sufficientto decreasethe outputcurrent
by 1% at the 1mAlevel.

SENSINGTEMPERATURE
The LM134, LM234, LM334 are excellent remote
controlled temperature sensors because their op-

erationas sourcesof currentpreservestheir accu­racyevenin the caseof longconnectingwires.The
outputcurrentisdirectlyproportionaltotheabsolute
temperaturein degreesKelvinaccording to thefol­lowing equation.

I

set

(227µV/

=

R

o

K)(T)

set

ThecalibrationoftheLM134,LM234,LM334is sim­plified by the factthat most of theinitial accuracyis
dueto gainlimitation (slopeerror)andnotan offset.
Gainadjustmentisa onepointtrimbecausetheout­putof thedevice extrapolates to zero at 0

Initial output

c

I

set

b

a

T1 T2 T30°K

b’

a’

Desired output

c’

o

K.

Thisparticularityof the LM134,LM234,LM334 is il­lustratedin theabove diagram.Lineabcrepresents
thesensorcurrentbeforeadjustmentandline a’b’c’
representsthedesiredoutput.Anadjustmentofthe
gain providedat T2 will move the outputfrom b to
b’and willcorrecttheslopeat thesametimeso that
theoutputatT1and T3will becorrect.Thisgainad­justment canbecarried out by meansof R

set

or the
loadresistorutilized in the circuit.After adjustment,
theslope error should be lessthan1%. A low tem­peraturecoefficientforR
accuracy. A 33ppm/

isnecessarytokeepthis

set

o

C temperaturedrift ofR

set

will
givean error of 1% onthe slope becausethe resis­tance follows the same temperaturevariations as
the LM134, LM234, LM334. Three wires are re­quired to isolate R
LM334. Since this solution is not recommended.
Metal-film resistorswith a driftless than20ppm/

from the LM134, LM234,

set

o

arenowavailable.Wirewound resistorscan be util­izedwhen very high stabilityis required.

C

5/10

LM134-LM234-LM334

TYPICAL APPL ICATIONS
Figure 1 : Basic 2-terminal Current Source

Figure 2 : Alternate Trimming Technique

V

i

V

ADJ

V

V

i

Figure 3 : Terminating Remote Sensor for

Voltage Output

R

set

V

i

V

ADJ

V

R

set

R1*

V

i

*For±10% adj ust me nt, se l ect Rset 10%

high and make R1

Figure 4 : Zero TemperatureCoefficient Current

Source

≈ 3Rset

VO=(I
R

set

R

L

6/10

)(RL) = 10mV/OK

set

= 230Ω

= 10kΩ

V

i

V

i

V

V

ADJ

i

ADJ

V

R

set

V

R

set

V

O

R

L

D1

1N 457

V

i

* S elect r at i o of R 1 to R

zero drift i

+

≈ 2I

set

to obtain

set

10

R1*

R

set

LM134-LM234-LM334

Figure 5 : Low Output ImpedanceThermometer

V > 4.8V

i

V

− R

R1

R2

o

16

Ω

where R

R3

V

O

is the equiva-

o

-

pin. This

ADJ

V

C1

R1 = 230Ω ,1% VO=10mV/oK
R2 = 10kΩ,1% Z
R3 = 600Ω
Output im pedance of t h e LM134, LM234, LM334 at the

”A DJ” pin is approximatel y
lent external resist ance connected to the V

negative r esistance can be reduced by a factor of 5 or
more by inserting an equivalent resistor in series with
the output

≤100Ω

O

FIgure 6 : Low Output ImpedanceThermometer

V

i

R1 R2

V

R1 = 15kΩ
R2 = 300Ω
R3 = 100Ω
R4 = 4.5kΩ
C1 = 2.2nF

= 10mV/OK

V

O

Z

≤ 2Ω

O

ADJ

C1

V

R3

R4

V

O

Figure 7 : Micropower Bias

V

R

ADJ

V

R

= 68kΩ

set

UA776

set

1µA

Figure 8 : Low Input Voltage Reference Driver

V

V

i

R1 = 1.5kΩ

V

i

R2 = 120Ω
C1 = 0.1µF

≤ 3mA

I

O

+

≥ Vref + 200mV

V

I

V

O=VZ

i

C1

+64mV (+25oC)

R1

2N2905

V

O

V

LM136

ADJ

V

R2

7/10

LM134-LM234-LM334

Figure 9 : In-line Current Limiter

R

set

ADJ

V

V

i

V

OP AMP

* U se min imum value requi r ed to ensur e

stability of protected circuit

C1*

Figure 10 : Fet Cascading for Low Capacitance

V

i

I

set

Q*

V > 1.2V

DS

V

ADJ

V

V

i

* S elect Q to ens ure at least 1V

across the LM 134, LM234, LM33 4.
V

(1–I

p

set/IDSS

) ≥ 1. 2V

R

set

8/10

PACKAG E MECHANI CAL DATA

8 PINS - PLASTIC MICROPACKAGE (SO)

LM134-LM234-LM334

Dimensions

Min. Typ. Max. Min. Typ. Max.

Millimeters Inches

A 1.75 0.069
a1 0.1 0.25 0.004 0.010
a2 1.65 0.065
a3 0.65 0.85 0.026 0.033

b 0.35 0.48 0.014 0.019

b1 0.19 0.25 0.007 0.010

C 0.25 0.5 0.010 0.020
c1 45

o

(typ.)
D 4.8 5.0 0.189 0.197
E 5.8 6.2 0.228 0.244

e 1.27 0.050

e3 3.81 0.150

F 3.8 4.0 0.150 0.157
L 0.4 1.27 0.016 0.050

M 0.6 0.024

S8

o

(max.)

PM-SO8.EPS

SO8.TBL

9/10

LM134-LM234-LM334

PACKAG E MECHANI CAL DATA

3 PINS - PLASTIC PACKAGE TO92

Dimensions

Min. Typ. Max. Min. Typ. Max.

Millimeters Inches

L 1.27 0.05
B 3.2 3.7 4.2 0.126 0.1457 0.1654

O1 4.45 5.00 5.2 0.1752 0.1969 0.2047

C 4.58 5.03 5.33 0.1803 0.198 0.2098

K 12.7 0.5

O2 0.407 0.5 0.508 0.016 0.0197 0.02

a 0.35 0.0138

Information furnished is believed to be accurate and reliable. However, SGS-THOMSON Microelectronics assumes no responsi­bility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which
may result from its use. No license is granted by implication or otherwise under any patent or patent rights of SGS-THOMSON
Microelectronics. Specification mentioned in this publication are subject to change without notice. This publication supersedes
and replacesall information previously supplied. SGS-THOMSON Microelectronics products are not authorized for use as critical
components in life support devices or systems without express written approval of SGS-THOMSON Microelectronics.

PM-TO92.IMG

TO92.TBL

 1997 SGS-THOMSON Microelectronics – Printed in Italy – All Rights Reserved

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