Features

■

■

■

■

Directly calibrated in °K

1°C initial accuracy

Operates from 450µA to 5mA

Less than 1

Ω

dynamic impedance

Description

The LM135, LM235, LM335 are precision temperature sensors which can be easily calibrated. They operate as a 2-terminal Zener and the breakdown voltage is directly proportional to the absolute temperature at 10mV/°K.

The circuit has a dynamic impedance of less than

1

Ω

and operates within a range of current from

450µA to 5mA without alteration of its characteristics.

Calibrated at +25°C, the LM135, LM235, and

LM335 have a typical error of less than 1°C over a

100°C temperature range. Unlike other sensors, the LM135, LM235, LM335 have a linear output.

LM135-LM235-LM335

Precision temperature sensors

TO-92

(Plastic package)

SO-8

(Plastic micropackage)

Pin connections

TO-92

(Bottom view)

ADJ v+ v-

SO-8

(Top view)

V+

8

NC

7

NC

6

ADJ

5

1

NC

2

NC

3

NC

4

V

-

February 2008 Rev 3 1/16

www.st.com

16

Schematic diagram

Figure 1.

Schematic diagram

LM135-LM235-LM335

2 Absolute maximum ratings

Table 1.

Symbol

Absolute maximum ratings (AMR)

Parameter LM135

T

I

I

R

F oper

Current

Reverse

Forward

Operating free-air temperature range

(1)

Continuous

Intermittent

T stg

Storage temperature range

1.

T j

≤

LM235

15

10

LM335-

LM335A

Unit

mA

-55 to +150

+150 to +200

-40 to +125

+125 to +150

-40 to +100

+100 to +125

-65 to +150

°C

°C

2/16

LM135-LM235-LM335 Temperature accuracy

Table 2.

Temperature accuracy

Parameter

Operating output voltage

T case

= +25°C, I

R

= 1mA

Uncalibrated temperature error (I

R

= 1mA)

T case

= +25°C

T min

≤

T case

≤ max

Temperature error with 25°C calibration

T min

≤ case

T max

.

, I

R

= 1mA

LM135 - LM235

LM335

LM335A

Calibrated error at extended temperature

T case

= T max

(intermittent)

Non-linearity (I

R

= 1mA)

LM135 - LM235

LM335

LM335A

LM135 - LM235 -

LM335A

LM335

Min.

Typ.

Max.

Min.

Typ.

Max.

Unit

2.95

2.98

3.01

2.92

2.98

3.04

1

2

3

5

4

5

6

9

V

°C

0.5

0.5

2

0.3

0.3

1.5

1

1

1.5

1 2

°C

2

0.3

1.5

°C

°C

Table 3.

Electrical characteristics

LM135 - LM235 LM335-LM335A

Parameter Unit

Min.

Typ.

Max.

Min.

Typ.

Max.

Operating output voltage change with current

450µA

≤

R

5mA at constant temperature

Dynamic impedance (I

R

= 1mA)

Output voltage temperature drift

Time constant

Still air

Air 0.5m/s

Stirred oil

Time stability (T case

= +125°C)

Note:

2.5

0.5

+10

80

10

1

0.2

10 3

0.6

+10

80

10

1

0.2

14

Accuracy measurements are made in a well-stirred oil bath. For other conditions, selfheating must be considered

mV

Ω mV/°C s

°C/kh

3/16

Electrical characteristics

Figure 2.

Reverse voltage change Figure 3.

Calibrated error

LM135-LM235-LM335

Reverse current (mA)

Figure 4.

Reverse characteristics

Temperature (°C)

Figure 5.

Response time

Reverse voltage (V)

Figure 6.

Dynamic impedance

Time (µs)

Figure 7.

Noise voltage

4/16

Frequency (Hz)

Frequency (Hz)

LM135-LM235-LM335 Electrical characteristics

Figure 8.

Thermal resistance junction to air Figure 9.

Thermal time constant

Air velocity (m/s)

Figure 10.

Thermal response in still air

Air velocity (m/s)

Figure 11.

Thermal response in stirred oil bath

Time (min)

Figure 12.

Forward characteristics

Time (s)

Forward current (mA)

5/16

Application information LM135-LM235-LM335

There is an easy method of calibrating the device for higher accuracies (see

Typical applications

).

The single point calibration works because the output of the LM135, LM235, LM335 is proportional to the absolute temperature with the extrapolated output of sensor going to 0V at 0°K (-273.15°C). Errors in output voltage versus temperature are only slope. Thus a calibration of the slope at one temperature corrects errors at all temperatures.

The circuit output (calibrated or not) is given by the equation:

V

OT

+ VO

TO x

To where T is the unknown temperature and To is the reference temperature (in °K).

Nominally, the output is calibrated at 10mV/°K.

Precautions should be taken to ensure good sensing accuracy. As in the case of all temperatures sensors, self-heating can decrease accuracy. The LM135, LM235, and LM335 should operate with a low current but sufficient to drive the sensor and its calibration circuit to their maximum operating temperature.

If the sensor is used in surroundings where the thermal resistance is constant, the errors due to self-heating can be externally calibrated. This is possible if the circuit is biased with a temperature stable current. Heating will then be proportional to Zener voltage and therefore temperature. In this way, the error due to self-heating is proportional to the absolute temperature as scale factor errors.

Typical applications

Figure 13.

Basic temperature sensor Figure 14.

Wide operating supply

6/16

LM135-LM235-LM335

Figure 15.

Calibrated sensor

Application information

Figure 16.

Average temperature sensing

*

Calibrated for 2.982V at 25°C

Figure 17.

Isolated temperature sensor

7/16

Application information

Figure 18.

Simple temperature controller

LM135-LM235-LM335

Figure 19.

Centigrade thermometer

8/16

LM135-LM235-LM335

Figure 20.

Differential temperature sensor

Application information

Figure 21.

Thermocouple cold junction compensation (compensation for grounded thermocouple)

9/16

Application information

Figure 22.

Single power supply cold junction compensation

LM135-LM235-LM335

10/16

LM135-LM235-LM335 Package information

6.1

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 box label, in compliance with JEDEC Standard JESD97. The maximum ratings related to soldering conditions are also marked on the inner box label. ECOPACK is an STMicroelectronics trademark. ECOPACK specifications are available at: www.st.com

.

TO-92 tape & reel package information

Figure 23.

TO-92 tape & reel package mechanical drawing

A1

P

P

T

H d

D0

P2

F1 F2

P0

11/16

Package information

Table 4.

Dim.

W2

H

H0

H1

DO

L1

I1

P

PO

P2

F1/F2

Δ h

Δ

P

W

W0

W1

AL

A

T d

TO-92 tape & reel package mechanical data

Millimeters

Min.

Typ.

Min.

Max.

5.0

5.0

4.0

0.45

2.5

11.7

12.4

5.95

2.4

-1

-1

17.5

5.7

8.5

15.5

3.8

12.7

12.7

6.35

2.5

0

0

18.0

6

9

16

4.0

0.5

20

16.5

25

4.2

11

13.7

13

6.75

2.8

1

1

19.0

6.3

9.75

0.098

0.461

0.488

0.234

0.094

-0.039

-0.039

0.689

0.224

0.335

0.610

0.150

LM135-LM235-LM335

Inches

Typ.

0.018

0.500

0.500

0.250

0.098

0

0

0.709

0.236

0.354

0.630

0.157

Max.

0.197

0.197

0.157

0.020

0.787

0.650

0.984

0.165

0.433

0.539

0.512

0.266

0.110

0.039

0.039

0.748

0.248

0.384

12/16

LM135-LM235-LM335

6.2 TO-92 bulk package information

Figure 24.

TO-92 bulk package mechanical drawing

Package information

Table 5.

Dim.

K

O2 a

L

B

O1

C

TO-92 bulk package mechanical data

Millimeters

Min.

Max.

3.2

4.45

4.58

12.7

0.407

0.35

Typ.

1.27

3.7

5.00

5.03

0.5

4.2

5.2

5.33

0.508

Min.

0.126

0.1752

0.1803

0.5

0.016

0.0138

Inches

Typ.

0.05

0.1457

0.1969

0.198

0.0197

Max.

0.1654

0.2047

0.2098

0.02

13/16

Package information

Figure 25.

SO-8 package mechanical drawing

LM135-LM235-LM335

14/16 c

D

H

E1

A

A1

A2 b

L k e h ccc

Table 6.

Ref.

SO-8 package mechanical data

Dimensions

Min.

Millimeters

Typ.

Min.

Max.

1.75

0.25

0.10

1.25

0.28

0.17

4.80

5.80

3.80

4.90

6.00

3.90

1.27

0.48

0.23

5.00

6.20

4.00

0.004

0.049

0.011

0.007

0.189

0.228

0.150

0.25

0.40

1°

0.50

1.27

8°

0.10

0.010

0.016

1°

Inches

Typ.

0.193

0.236

0.154

0.050

Max.

0.069

0.010

0.019

0.010

0.197

0.244

0.157

0.020

0.050

8°

0.004

LM135-LM235-LM335 Ordering information

Table 7.

Order codes

Order code

Temperature range

-55°C to +150°C LM135Z

LM235D

LM235DT

LM235Z

LM335D

LM335DT

LM335AD

LM335ADT

LM335Z

LM335AZ

LM335AZT

-40°C to +125°C

-40°C to +125°C

-40°C to +100°C

-40°C to +100°C

Package

TO-92

SO-8

TO-92

SO-8

TO-92

Packing Marking

Bulk

Tube or

Tape & reel

Bulk

LM135

LM235

LM235

LM335

Tube or

Tape & reel

LM335A

Bulk LM335

Bulk or

Tape & reel

LM335A

Table 8.

Date

6-May-2003

Document revision history

13-April-2004

11-Feb-2007

Revision

1

2

3

Changes

Initial release.

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

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

Updated

Section 6: Package information

and

Table 7: Order codes

.

Corrected typical values for uncalibrated temperature error in

Table 2

.

Improved quality of electrical characteristics curves.

15/16

LM135-LM235-LM335

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