1/11
■OPERATES FROM 1V TO 40V
■0.02%/V CURRENT REGULATION
■PROGRAMMABLE FROM 1µA TO 10mA
■±3% INITIAL ACCU RACY
DESCRIPTION
The LM134/LM234/LM334 are 3-terminal adjust-
able current sources characterized by:
❑an operating current range of 10000: 1
❑an excellent current regulatio n
❑a wide dynamic voltage range of 1V t 10V
The current is determined by an external resistor
without requiring other external compone nts.
Reverse voltages of up to 20V will only draw a cur-
rent 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/LM334, the voltage on the
control pin is 64mV at +25°C and is directly pro-
portional to the absolute temperature (°K). The
simplest ext ernal resistor c onnection 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.
ORDER CODE
Z = T O92 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)
PIN CONNECTIONS (top view)
Part Number Temperature
Range Package
ZD
LM134 -55°C, +125°C ••
LM234 -25°C, +100°C ••
LM334 0°C, +70° C ••
Z
TO92
(Plastic Package)
D
SO8
(Plastic Micro packa ge)
ADJ
v+
v-
21 3
8765
1234
NC NC V- NC
ADJ NC NC V+
TO92
(Top view) SO8
(Top view)
LM134
LM234 - LM334
THREE TERMINAL ADJUSTABLE CURRENT SOURCES
May 2003
LM134 - LM234 - LM334
2/11
SCHEMATIC DIAGRAM
ABSOLUTE MAXIMUM RATINGS
Symbol Parameter LM134 LM234 LM334 Unit
Voltage V+ to V-
Forward
Reverse 40
20 30
20 V
VADJ-ADJ Pin to V- Voltage 5V
I
SET Set Current 10 mA
Ptot Power Dissipation 400 mW
TStg Storage Temperature Range -65 to +150 °C
Toper Operating Free-air Temperature Range -55 to +125 -25 to +100 0 to +70 °C
LM134 - LM234 - LM334
3/11
ELECTRICAL CHARACTERISTICS
Tj = +25°C wit h pulse testing so that junction temperature does not change during testing (unless
otherwise specified)
Parameter LM134 - LM234 LM334 Unit
Min. Typ. Max. Min. Typ. Max.
Set Current Error (V+ = +2.5V) -1)
10µA ≤ ISET ≤ 1mA
1mA ≤ ISET ≤ 5mA
2µA ≤ ISET ≤ 10µA
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 expresse d as a per cent deviat i on f rom this amount
3
5
8
6
8
12
%
Ratio of Set Current to V- Current
10µA ≤ ISET ≤ 1mA
1mA ≤ ISET ≤ 5mA
2µA ≤ ISET ≤ 10µA
14 18
14
14
23 14 18
14
14
26
Minimum Opera ting Voltag e
2µA ≤ ISET ≤ 100µA
100µA ≤ ISET ≤ 1mA
1mA ≤ ISET ≤ 5mA
0.8
0.9
1
0.8
0.9
1
V
Average Change in Set Current with Input Voltage
2µA ≤ ISET ≤ 1mA
+1.5V ≤ V+ ≤ +5V
+5V ≤ V+ ≤ +40V
1mA ≤ ISET ≤ 5mA
+1.5V ≤ V+ ≤ +5V
+5V ≤ V+ ≤ +40V
0.02
0.01
0.03
0.02
0.05
0.03 0.02
0.01
0.03
0.02
0.1
0.05 % / V
Temperature Dependence of set current - 2)
25µA ≤ ISET ≤ 1mA
2. Iset i s di rectly pro port io nal to absol ute tem perature (° K). Is et at any temperature can b e calculated from I set = Io (T/ T o) where Io is Iset
meas ured at To (°K)
0.96 T T 1.04 T 0.96 T T 1.04 T
Effective Shunt Capacitance 15 15 pF
LM134 - LM234 - LM334
4/11
LM134 - LM234 - LM334
5/11
APPLICATION HINTS
SLEW RATE
At slew rates above a threshold (see curve) the
LM134, LM234, LM334 can have a non-linear cur-
rent 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 high
currents.
TH E R MAL EFFE CTS
Internal heating can have a significant effect on
current regulation for an Iset above 100µA. For ex-
ample, 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 the change in current due
to the increase in temperature will be (0.4) (0.33) =
0.132 % . This is degradat ion of 10 : 1 in regulation
versus the true electrical effects. Thermal effects
sho uld 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
shu nt capacitance sh ould 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 val ue of this capacitance 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 f or the minimum in-
put voltage).
NOISE
The current noise produced by LM134, LM234,
LM33 4 is about 4 times that of a transistor. If the
LM13 4, 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 ac-
ceptable, and a single amplifier can be built with a
voltag e 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 locat-
ing the current setting resistor close to the device.
Do not use sockets for the ICs. A contact resis-
tance of 0.7Ω is sufficient to decrease the output
current by 1% at the 1mA level.
SENSI N G TEMPER ATURE
The LM134, LM234 , LM334 are excellent remote
con trolled t emperature s ensors because t heir op-
eration as current sources preserves their accura-
cy even in the case of long connec ting wires. T he
outpu t current is direct ly proportional to the abso-
lute temperature in Kelvin degrees according to
the following equation.
The calibration of the LM134, LM234, LM334 is
simplified by the f act that most of the initial accura-
cy is due to gain limitation (slope error) and not an
offset. Gain adjustment is a one point trim be-
cause the output of the device extrapolates to zero
at 0°K.
This particularity of the LM13 4, LM234, LM 334 is
illustrated in the above diagram. Line abc repre-
sents 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’ and wil l correct the slope at the s am 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 l oad resistor used in the circuit. After
adjustment, the slope error should be less than
1% . A low temperat ure coef ficient for Rset is nec -
essary to keep this accuracy. A 33ppm/°C temper-
ature drift of Rset will give an error 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, LM234, LM334. Since this solu-
tion is not recommen ded. Metal-film resistors with
a drift less than 20ppm/°C are now available.
W irewoun d resi stors can b e u se d when very hi gh
stability is required.
Iset = 227µV/°K) (T
()
Rset
-----------------------------------------
LM134 - LM234 - LM334
6/11
LM134 - LM234 - LM334
7/11
LM134 - LM234 - LM334
8/11
LM134 - LM234 - LM334
9/11
PACKAGE MECHANICAL DATA
DIM. mm. inch
MIN. TYP MAX. MIN. TYP. MAX.
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
SO-8 MECHANICAL DATA
0016023/C
8
LM134 - LM234 - LM334
10/11
PACKAGE MECHANICAL DATA - TO92 TAPE AMMO PACK & TO92 TAPE & REEL
Packing information are available at: http://www.st.com/stonline/prodpres/packages/stdlin.htm
DIM. mm. inches
MIN. TYP MAX. MIN. TYP. MAX.
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
Dh -1 0 1 -0.039 0 0.039
DP -1 0 1 -0.039 0 0.039
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
TO-92 MECHANICAL DATA
LM134 - LM234 - LM334
11/11
PACKAGE MECHANICAL DATA - TO92 BULK
Packing information are available at: http://www.st.com/stonline/prodpres/packages/stdlin.htm
DIM. mm. mils
MIN. TYP MAX. MIN. TYP. MAX.
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
TO-92 MECHANICA DATA
0102782/C
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