STMicroelectronics LM134, LM234, LM334 Technical data

ADJ

v+

v-

21

3

LM134

LM234 - LM334

THREE TERMINAL ADJUSTABLE CURRENT SOURCES

■ OPERATES FROM 1V TO 40V

■ 0.02%/V CURRENT REGULATION

■ PROGRAMMABLE FROM 1µA TO 10mA

■ ±3% INITIAL ACCURACY

DESCRIPTION

The LM134/LM234/LM334 are 3-terminal adjust­able current sources characterized by:

❑ an operating current range of 10000: 1
❑ an excellent current regulation
❑ a wide dynamic voltage range of 1V t 10V

The current is determined by an external resistor
without requiring other external components.

Reverse voltages of up to 20V will only draw a cur­rent of several microamperes. This enables the
circuit to operate as a rectifier and as a so urce of
current in a.c. applications.

For the LM134/LM234/LM33 4, the voltage on the
control pin is 64m V at +25°C and is direct ly pro­portional to the absolute temperature (°K). The
simplest external resistor conn ection ge nerates a
current with ≈ 0.33%/°C temperature dependence.
Zero drift can be obtained by adding an additional
resistor and a diode to the external circuit.

Z

TO92

(Plastic Package)

D

SO8

(Plastic Micropacka ge)

ORDER CODE

Part Number

LM134 -55°C, +125°C
LM234 -25°C, +100°C
LM334 0°C, +70°C

Z = TO92 Plastic package - also available in Bulk (Z), Tape & Reel (ZT)
and Ammo Pack (AP)

D = Small Outline Package (SO) - also available in Tape & Reel (DT)

Temperature

Range

Package
ZD

••

••

••

PIN CONNECTIONS (top view)

TO92

(Top view)

May 2003

SO8

(Top view)

NC NCV-NC

8765

1234

ADJNCNC

V+

1/11

LM134 - LM234 - LM334

SCHEMATIC DIAGRAM

ABSOLUTE MAXIMUM RATINGS

Symbol Parameter LM134 LM234 LM334 Unit

Voltage V+ to V-

Forward
Reverse

-

V

I

P

T

ADJ Pin to V- Voltage

ADJ

Set Current 10 mA

SET

Power Dissipation 400 mW

tot

Storage Temperature Range -65 to +150 °C

Stg

Toper Operating Free-air Temperature Range -55 to +125 -25 to +100 0 to +70 °C

40
20

30
20

5V

V

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LM134 - LM234 - LM334

ELECTRICAL CHARACTERISTICS

Tj = +25°C with pulse testing so that junction temperature does not change during testing (unless
otherwise specified)

Parameter

Set Current Error (V

10µA ≤ I
1mA ≤ I
2µA ≤ I

Ratio of Set Current to V

10µA ≤ I
1mA ≤ I
2µA ≤ I

+

= +2.5V) -1)

≤ 1mA

SET

≤ 5mA

SET

≤ 10µA

SET

≤ 1mA

SET

≤ 5mA

SET

≤ 10µA

SET

Current

-

Minimum Operating Voltage

2µA ≤ I
100µA ≤ I
1mA ≤ I

≤ 100µA

SET

SET

≤ 5mA

SET

≤ 1mA

Average Change in Set Current with Input Voltage

2µA ≤ I

1mA ≤ I

Temperature Dependence of set current -

25µA ≤ I

≤ 1mA

SET

+1.5V ≤ V
+5V ≤ V

≤ 5mA

SET

+1.5V ≤ V
+5V ≤ V

≤ 1mA

SET

≤ +5V

+

≤ +40V

+

≤ +5V

+

≤ +40V

+

2)

Effective Shunt Capacitance 15 15 pF

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

3
5
8

23 14 18

1

0.05

0.03

14
14

0.8

0.9
1

0.02

0.01

0.03

0.02

6
8

12

26

0.1

0.05 % / V

0.96 T T 1.04 T 0.96 T T 1.04 T

Unit

%

V

1. Set current is the current flowing into the V+ pin. It is determined by the following formula Iset = 67.7mV/Rset (Tj = +25°C)
Set curren t e rror is expressed as a percent devi at i on from this am ount

2. Iset is directly propor tional to ab solute temperature (° K). Iset at any t em perature can be calculated from I set = Io (T/To) where Io is Iset
measured a t To (°K)

3/11

LM134 - LM234 - LM334

4/11

LM134 - LM234 - LM334

APPLICATION HINTS

SLEW RATE
At slew rates above a threshold (see curve) the

LM134, LM234, LM334 can have a non-linear cur­rent characteristic. The slew rate at which this
takes place is directly proportional to Iset. At Iset =

10µA, dv/dt max. = 0.01V/µs ; at Iset = 1mA, dv/dt
max. = 1V/µs. Slew rates of more than 1V/µs do
not damage the circuit nor do they produce hi gh
currents.

THERMAL EFFE C T S

Internal heating can have a significant effect on
current regulation for an Iset above 100µA. For ex­ample, each increase of 1V in the voltage across
the LM134 at Iset = 1mA will increase the junction
temperature by ≈ 0.4°C (in still air). The output
current (Iset) has a temperature coefficient of
about 0.33%/°C. Thus t he change in current due
to the increase in temperature will be (0.4) (0.33) =

0.132%. This is degradation of 10 : 1 in regulation

versus the true electrical effects. Thermal effe cts
should be taken into account when d.c. regulation
is critical and Iset is higher than 100µA.

SHUNT CAPACITANCE

In certain applications, the 15pF value for the
shunt capacitance should be reduced :

❑ because of loading problems,
❑ because of limitation of output imped ance

of the current source in a.c. applications.
This reduction of capacitance can be easily
carried out by adding a FET as indicated in
the typical applications.

The value of this c apacitance can b e reduced by
at least 3pF and regulation can be improved by an
order of magnitude without any modifications of
the d.c. characteristics (except for the minimum in­put voltage).

NOISE

The current noise produced by LM134, LM234,
LM334 is about 4 tim es that of a transistor. If the
LM134, LM234, LM334 is used as an active lo ad
for a transistor amplifier, 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
voltage gain higher than 2000.

LEAD RESISTANCE

The sense voltage which determines the current
of the LM134, LM234, LM334 is less than 100mV.
At this level, the thermocouple effects and the
connection resistance should be reduced by locat­ing the current setting resistor close to the device.
Do not use sockets for the ICs. A contact resis­tance of 0.7Ω is sufficient to decrease the output
current by 1% at the 1mA level.

SENSING TEMPERAT URE

The LM134, LM234 , LM334 are excellen t remote
controlled temperature s ensors because t heir op­eration as current sources preserves their accura­cy even in the case of long connecting wires. T he
output current is directly proportional to the abso­lute temperature in Kelvin degrees according to
the following equation.

227µV/°K) (T

()

Iset =

----------------------------------------­Rset

The calibration of the LM134, LM234, LM334 is
simplified by the fact that most of the initial accura­cy is due to gain limitation (slope error) and not an
offset. Gain adjustment is a one point trim be­cause the output of the device extrapolates to zero
at 0°K.

This particularity of the LM134, LM234, LM334 is
illustrated in the above diagram. Line abc repre­sents the sensor current before adjustment and
line a’b’c’ represents the desired output. A gain
adjustment provided at T2 will move the output
from b to b’ an d will correc t the slope at the sam e
time so that the output at T1 and T3 will be correct.
This gain adjustment can be carried out by means
of Rset or the load resistor used in the circuit. After
adjustment, the slope error should be less than
1%. A low temperature coefficient for Rset is nec ­essary to keep this accuracy. A 33ppm/°C temper­ature drif t of Rset w ill give an erro r of 1% on the
slope because the resistance follows the same
temperature variations as the LM134, LM234,
LM334. Three wires are required to isolate Rset
from the LM134, LM2 34, LM334. Since this solu­tion is not recommended. Metal-film resistors with
a drift less than 20ppm/°C are now available.
Wirewound resistors can be use d w hen very high
stability is required.

5/11

LM134 - LM234 - LM334

6/11

LM134 - LM234 - LM334

7/11

LM134 - LM234 - LM334

8/11

LM134 - LM234 - LM334

PACKAGE MECHANICAL DATA

SO-8 MECHANICAL DATA

DIM.

A 1.35 1.75 0.053 0.069
A1 0.10 0.25 0.04 0.010
A2 1.10 1.65 0.043 0.065

B 0.33 0.51 0.013 0.020

C 0.19 0.25 0.007 0.010

D 4.80 5.00 0.189 0.197

E 3.80 4.00 0.150 0.157

e 1.27 0.050

H 5.80 6.20 0.228 0.244

h 0.25 0.50 0.010 0.020

L 0.40 1.27 0.016 0.050

k ˚ (max.)

ddd 0.1 0.04

MIN. TYP MAX. MIN. TYP. MAX.

mm. inch

8

9/11

0016023/C

LM134 - LM234 - LM334

PACKAGE MECHANICAL DATA - TO92 TAPE AMMO PACK & TO92 TAPE & REEL

TO-92 MECHANICAL DATA

DIM.

AL 5.0 0.197

A 5.0 0.197
T 4.0 0.157
d 0.45 0.018

I1 2.5 0.098

P 11.7 12.7 13.7 0.461 0.500 0.539

PO 12.4 12.7 13 0.488 0.500 0.512

P2 5.95 6.35 6.75 0.234 0.250 0.266

F1/F2 2.4 2.5 2.8 0.094 0.098 0.110

h -1 0 1 -0.039 0 0.039

D

P -1 0 1 -0.039 0 0.039

D

W 17.5 18.0 19.0 0.689 0.709 0.748
W0 5.7 6 6.3 0.224 0.236 0.248
W1 8.5 9 9.75 0.335 0.354 0.384
W2 0.5 0.020

H 20 0.787

H0 15.5 16 16.5 0.610 0.630 0.650
H1 25 0.984

DO 3.8 4.0 4.2 0.150 0.157 0.165

L1 11 0.433

MIN. TYP MAX. MI N. TYP. MAX.

mm. inches

Packing information are available at: http://www.st.com/stonline/prodpres/packages/stdlin.htm

10/11

LM134 - LM234 - LM334

PACKAGE MECHANICAL DATA - TO92 BULK

TO-92 MECHANICA DATA

DIM.

A 4.32 4.95 170.1 194.9

b 0.36 0.51 14.2 20.1

D 4.45 4.95 175.2 194.9

E 3.30 3.94 129.9 155.1

e 2.41 2.67 94.9 105.1

e1 1.14 1.40 44.9 55.1

L 12.7 15.49 500.0 609.8

R 2.16 2.41 85.0 94.9

S1 0.92 1.52 36.2 59.8

W 0.41 0.56 16.1 22.0

MIN. TYP MAX. MIN. TYP. MAX.

mm. mils

0102782/C

Packing information are available at: http://www.st.com/stonline/prodpres/packages/stdlin.htm

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