LM334Z - STMicroelectronics

May 2007 Rev 3 1/16

LM134-LM234-LM334

Three terminal adjustable current sources

Features

■Operates from 1V t o 40V

■0.02%/V current regulation

■Programmab le fro m 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 se veral microamperes. This enables the

circuit to operate as a rectifier and as a source of

current in a.c. applications.

For the LM134/LM234/LM334, the vo ltage on the

control pin is 64mV at +25° C and is di re ct ly

proportional to the absolute temperature (°K). The

simplest external resistor connection g enerates a

current with a ppro x imately 0.33%/°C temper ature

dependence . Zero drift can be obtained b y adding

an additional resistor an d a diode to the external

circuit.

TO-92

(Plastic package)

SO-8

(Plastic micropackage)

ADJ

21 3

TO-92

(Bottom view)

8765

1234

NC NC V- NC

ADJ NC NC V+

SO-8

(Top view)

Pin connections

www.st.com

Schematic diagra m LM134-LM234-LM334

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1 Schematic diagram

Figure 1. Schematic diagram

2 Absolute maximum ratings

Table 1. 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 5 V

Iset 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 Electrical characteristics

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3 Electrical characteristics

Tj = +25°C with pulse testing so that junction temperature does not change during testing

(unless otherwise specified)

Table 2. Electrical characteristi cs

Parameter LM134 - LM234 LM334 Unit

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

Set current error (V+ = +2.5V) -(1)

10µA ≤ I

set ≤ 1mA

1mA ≤ I

set ≤ 5mA

2µA ≤ Iset ≤ 10µA

Ratio of set current to V- current

10µA ≤ I

set ≤ 1mA

1mA ≤ I

set ≤ 5mA

2µA ≤ Iset ≤ 10µA

14 18

23 14 18

Minimum operating voltage

2µA ≤ I

set ≤ 100µA

100µA ≤ I

set ≤ 1mA

1mA ≤ Iset ≤ 5mA

0.8

0.9

0.8

0.9

Average change in set current with input voltage

2µA ≤ I

set ≤ 1mA

+1.5V ≤ V

+ ≤ +5V

+5V ≤ V

+ ≤ +40V

1mA ≤ I

set ≤ 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 0.96 T T 1.04 T 0.96 T T 1.04 T

Effective shunt capacitance 15 15 pF

1. The set current is the current flowing into the V+ pin. It is determined by the following formula:

Iset = 67.7mV/Rset (Tj = +25°C)

The set current error is expressed as a percent deviation from this amount.

2. 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).

Electrical characteristics LM134-LM234-LM334

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Figure 2. Output impedance Figure 3. Maximum slew rate for linear

operation

Impedance (Ohm)

Frequency (Hz)

Slew rate (V/µs)

Iset (µA)

Figure 4. Startup Figure 5. Transient response

Time (scale changes at each cur rent level) Time (scale changes at each cur rent level)

Figure 6. Voltage across Rset Figure 7. Current noise

Voltage (mV)

Temper ature (°C)

Current (pA/√Hz)

Frequency (Hz)

LM134-LM234-LM334 Electrical characteristics

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Figure 8. Turn-on voltage Figure 9. Ratio of Iset to V- current

Iset (mA)

V+ to V- voltage (V)

Ratio

Iset (mA)

Application information LM134-LM234-LM334

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4 Application information

4.1 Slew rate

At sle w rates a bov e a thre shold (see Figure 4 and Figure 5), the LM134 , LM234, LM334 can

have a non-linear current characteristic. The slew rate at which this takes place is directly

proportion al 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 no t damage the circuit nor do they produce high currents.

4.2 Thermal effects

Internal heating can have a signif icant 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 the change in current due to the increase

in temperature will be (0.4) (0.33) = 0.132%. This is a degradation of 10 : 1 in regulation

versus the true electrical effects. Thermal effects should be taken into account when d.c.

regulation is critical and Iset is higher than 100µA.

4.3 Shunt capacitance

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

●because of loading problems,

●because of limitat ion of output impedance of the current source in a.c. applications.

You can e asily redu ce the capa citance by adding a FET as sho wn in Ty pical ap plications on

page 8.

The value of this capacitance can be 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 mini mum input voltage).

4.4 Noise

The current noise pr oduced by LM 134, LM234, and LM334 is about 4 times that of a

transistor. If the LM134, LM234, LM334 is used as an acti ve load f or 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.

4.5 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 socke ts for

the ICs. A contact resistance of 0.7Ω is sufficient to decrease the output current b y 1% at the

1mA level.

LM134-LM234-LM334 Application information

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4.6 Sensing temperature

The LM134, LM234, LM334 are excellent remote controlled temperature sensors because

their oper ation as current sources preserves their accuracy even in the case of long

connecting wires. The output current is directly proportional to the absolute temperature in

Kelvin degrees according to the following equation.

The calibrat ion of the LM134, LM234, LM334 is simplified by the fact that most of the initial

accuracy is due to ga in 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.

Figure 10. Device calibration

This particularity of the LM134, LM234, LM334 is illustrated in the above diagram. Line abc

represents the senso r 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 will correct

the slope at the same 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 err or should be less than 1%. A lo w temper ature coef ficient for Rset is

necessary to keep this accuracy. A 33ppm/°C temperature 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 r equired to isolat e Rset from th e LM13 4, LM2 34, LM33 4. Since this soluti on

is not recommended, metal-film resistors with a drift of less than 20ppm/°C are now

available. Wirewound resistors can be used when very high stability is requ ired.

Iset = 227µV/°K) (T()

Rset

-----------------------------------------

Application information LM134-LM234-LM334

8/16

Typical applications

Figure 11. B asic 2-terminal current source Figure 12. Alternate trimming technique

Figure 13. Terminating remote sensor for

vo ltage output Figure 14. Zero temperature coefficient

current source

LM134-LM234-LM334 Application information

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Figure 15. Low output impedance

thermometer Figure 16. Low output impedance

thermometer

Figure 17. Micropower bias Figure 18. Low input voltage reference driver

Application information LM134-LM234-LM334

10/16

Figure 19. In-line current limiter Figure 20. Fet cascading for low capacitance

LM134-LM234-LM334 Package information

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5 Package information

In order to meet environmental requirements, STMicroelectronics offers these devices in

ECOPACK® packages. These packages have a lead-free second level interconnect. The

category of second level interconnect is marked on the package and on the inner bo x label,

in compliance with JEDEC Standard JESD97. The maximum ratin gs rela ted to soldering

conditions are also marked on the inner box label. ECOPACK is an STMicroelectronics

tradem ark. ECOPACK specification s are available at: www.st.com.

Package information LM134-LM234-LM334

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5.1 SO-8 package mechanical data

Ref.

Dimensions

Millimeters Inches

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

A1.750.069

A1 0.10 0.25 0.004 0.010

A2 1.25 0.049

b 0.28 0.48 0.011 0.019

c 0.17 0.23 0.007 0.010

D 4.80 4.90 5.00 0.189 0.193 0.197

H 5.80 6.00 6.20 0.228 0.236 0.244

E1 3.80 3.90 4.00 0.150 0.154 0.157

e 1.27 0.050

h 0.25 0.50 0.010 0.020

L 0.40 1.27 0.016 0.050

k1°8°1°8°

ccc 0.10 0.004

LM134-LM234-LM334 Package information

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5.2 TO-92 ammopack and tape & reel package mechanical data

Dim. Millimeters 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

Δh -1 0 1 -0.039 0 0.039

ΔP -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

H200.787

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

F1 F2

Package information LM134-LM234-LM334

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5.3 TO-92 bulk package mechanical data

Dim. Millimeters Inches

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

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

K12.7 0.5

O2 0.407 0.5 0.508 0.016 0.0197 0.02

a 0.35 0.0138

LM134-LM234-LM334 Ordering information

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6 Ordering information

7 Revision history

Table 3. Order codes

Part number Temperature

range Package Packing Marking

LM134D/DT -55°C to +125°C SO-8 Tube or

Tape & reel LM134

LM134Z/ZT/AP -55°C to +125°C TO-92 Bulk or

Tape & reel or

Ammopack LM134

LM234D/DT -25°C to +100°C SO-8 Tube or

Tape & reel LM234

LM234Z/ZT/AP -24°C to +100°C TO-92 Bulk or

Tape & reel or

Ammopack LM234

LM334D/DT -0°C to +70°C SO-8 Tube or

Tape & reel LM334

LM334Z/ZT/AP -0°C to +70°C TO-92 Bulk or

Tape & reel or

Ammopack LM334

LM334AD/ADT -0°C to +70°C SO-8 Tube or

Tape & reel LM334A

LM334AZ/AZT/AAP -0°C to +70°C TO-92 Bulk or

Tape & reel or

Ammopack LM334A

Date Revision Changes

2-Ma y-2003 1 Initial release.

28-Oct-2005 2 Internal revision.

29-May-2007 3

Corrected error in pinout diagram for TO -92 package on cover page

(it is a bottom view, not a top view).

Updated Section 5: Package information and expanded Table 3:

Order codes.

LM134-LM234-LM334

16/16

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