LM35/LM35A/LM35C/LM35CA/LM35D

Precision Centigrade Temperature Sensors

General Description
The LM35 series are precision integrated-circuit temperature
sensors, whose output voltage is linearly proportional to the
Celsius (Centigrade) temperature. The LM35 thus has an
advantage over linear temperature sensors calibrated in
Kelvin, as the user is not required to subtract a large constant voltage from its output to obtain convenient Centigrade
scaling. The LM35 does not require any external calibration
or trimming to provide typical accuracies of 14C at room
temperature and 34C over a full 55 to +150C temperature range. Low cost is assured by trimming and calibration
at the wafer level. The LM35s low output impedance, linear
output, and precise inherent calibration make interfacing to
readout or control circuitry especially easy. It can be used
with single power supplies, or with plus and minus supplies.
As it draws only 60 A from its supply, it has very low
self-heating, less than 0.1C in still air. The LM35 is rated to
operate over a 55 to +150C temperature range, while the
LM35C is rated for a 40 to +110C range (10 with improved accuracy). The LM35 series is available packaged in

hermetic TO-46 transistor packages, while the LM35C,

LM35CA, and LM35D are also available in the plastic TO-92
transistor package. The LM35D is also available in an 8-lead
surface mount small outline package and a plastic TO-220
package.

Features
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Calibrated directly in Celsius (Centigrade)

Linear + 10.0 mV/C scale factor
0.5C accuracy guaranteeable (at +25C)
Rated for full 55 to +150C range
Suitable for remote applications
Low cost due to wafer-level trimming
Operates from 4 to 30 volts
Less than 60 A current drain
Low self-heating, 0.08C in still air
Nonlinearity only 14C typical
Low impedance output, 0.1 for 1 mA load

Typical Applications

DS005516-4
DS005516-3

FIGURE 1. Basic Centigrade Temperature Sensor

(+2C to +150C)

Choose R1 = VS/50 A
VOUT = +1,500 mV at +150C
= +250 mV at +25C
= 550 mV at 55C

FIGURE 2. Full-Range Centigrade Temperature Sensor

TRI-STATE is a registered trademark of National Semiconductor Corporation.

1999 National Semiconductor Corporation

DS005516

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LM35/LM35A/LM35C/LM35CA/LM35D Precision Centigrade Temperature Sensors

September 1997

Connection Diagrams
TO-46
Metal Can Package*

SO-8
Small Outline Molded Package

DS005516-1

DS005516-21

N.C. = No Connection

*Case is connected to negative pin (GND)

Order Number LM35H, LM35AH, LM35CH, LM35CAH or

LM35DH
See NS Package Number H03H

Top View
Order Number LM35DM
See NS Package Number M08A

TO-92
Plastic Package

TO-220
Plastic Package*

DS005516-2

Order Number LM35CZ,

LM35CAZ or LM35DZ
See NS Package Number Z03A

DS005516-24

*Tab is connected to the negative pin (GND).

Note: The LM35DT pinout is different than the discontinued LM35DP.

Order Number LM35DT

See NS Package Number TA03F

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Absolute Maximum Ratings (Note 10)

TO-92 and TO-220 Package,

(Soldering, 10 seconds)
260C
SO Package (Note 12)
Vapor Phase (60 seconds)
215C
Infrared (15 seconds)
220C
ESD Susceptibility (Note 11)
2500V
Specified Operating Temperature Range: TMIN to TMAX
(Note 2)
LM35, LM35A
55C to +150C
LM35C, LM35CA
40C to +110C
LM35D
0C to +100C

If Military/Aerospace specified devices are required,

please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Supply Voltage
Output Voltage
Output Current
Storage Temp.;
TO-46 Package,
TO-92 Package,
SO-8 Package,
TO-220 Package,
Lead Temp.:
TO-46 Package,
(Soldering, 10 seconds)

+35V to 0.2V
+6V to 1.0V
10 mA
60C
60C
65C
65C

to
to
to
to

+180C
+150C
+150C
+150C

300C

Electrical Characteristics
(Notes 1, 6)
LM35A
Parameter

Conditions
Typical

Accuracy
(Note 7)

TMINTATMAX

0.2
0.3
0.4
0.4
0.18

TMINTATMAX

+10.0

TA = +25C
TA = 10C
TA = TMAX
TA = TMIN

Nonlinearity

LM35CA

Tested

Design

Limit

Limit

(Note 4)

(Note 5)

0.5
1.0
1.0
0.35

Typical

0.2
0.3
0.4
0.4
0.15

Tested

Design

Units

Limit

Limit

(Max.)

(Note 4)

(Note 5)

0.5

1.0

1.5
0.3

C
C

+9.9,

mV/C

1.0

(Note 8)
Sensor Gain
(Average Slope)
Load Regulation

TA = +25C

(Note 3) 0IL1 mA

TMINTATMAX
TA = +25C

Line Regulation
(Note 3)
Quiescent Current
(Note 9)

+9.9,

+10.0

+10.1

4VVS30V
VS = +5V, +25C
VS = +5V
VS = +30V, +25C
VS = +30V

0.4
0.5
0.01
0.02
56

1.0
3.0
0.05
0.1
67

105
56.2

+10.1

56
131

68

105.5

0.4
0.5
0.01
0.02

mV/mA

3.0

mV/mA

0.1

mV/V

0.05

mV/V

67

91
56.2

133

1.0

A
114

68

91.5

A
A

116

Change of

4VVS30V, +25C

0.2

Quiescent Current

4VVS30V

0.5

2.0

0.5

2.0

+0.39

+0.5

+0.39

+0.5

A/C

+1.5

+2.0

+1.5

+2.0

1.0

0.2

1.0

(Note 3)
Temperature
Coefficient of
Quiescent Current
Minimum Temperature

In circuit of

for Rated Accuracy

Figure 1, IL = 0
TJ = TMAX, for

Long Term Stability

0.08

0.08

1000 hours

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Electrical Characteristics
(Notes 1, 6)
LM35
Parameter

Conditions

Design

Limit

Limit

(Note 4)

(Note 5)

Typical
Accuracy,
LM35, LM35C
(Note 7)
Accuracy, LM35D
(Note 7)
Nonlinearity

0.4
0.5
0.8
0.8

TA = +25C
TA = 10C
TA = TMAX
TA = TMIN
TA = +25C

LM35C, LM35D

Tested

1.0
1.5
1.5

TA = TMAX
TA = TMIN
TMINTATMAX

0.3

TMINTATMAX

+10.0

0.5

Typical

0.4
0.5
0.8
0.8
0.6
0.9
0.9
0.2

Tested

Design

Units

Limit

Limit

(Max.)

(Note 4)

(Note 5)

1.0

1.5
1.5
2.0

2.0
2.0
0.5

+9.8,

mV/C

1.5

C
C
C
C
C

(Note 8)
Sensor Gain
(Average Slope)
Load Regulation

TA = +25C

(Note 3) 0IL1 mA

TMINTATMAX
TA = +25C

Line Regulation
(Note 3)
Quiescent Current
(Note 9)

+9.8,

+10.0

+10.2

4VVS30V
VS = +5V, +25C
VS = +5V
VS = +30V, +25C
VS = +30V

0.4
0.5
0.01
0.02

2.0

56

80

+10.2

5.0
0.1
0.2

105

158

56.2

82

105.5

0.4
0.5
0.01
0.02

2.0

56

80

161

mV/mA

0.2

mV/V

0.1

91
56.2

mV/mA

5.0

mV/V
A
138

82

91.5

A
A

141

Change of

4VVS30V, +25C

0.2

Quiescent Current

4VVS30V

0.5

3.0

0.5

3.0

+0.39

+0.7

+0.39

+0.7

A/C

+1.5

+2.0

+1.5

+2.0

2.0

0.2

2.0

(Note 3)
Temperature
Coefficient of
Quiescent Current
Minimum Temperature

In circuit of

for Rated Accuracy

Figure 1, IL = 0
TJ = TMAX, for

Long Term Stability

0.08

0.08

1000 hours
Note 1: Unless otherwise noted, these specifications apply: 55CTJ+150C for the LM35 and LM35A; 40TJ+110C for the LM35C and LM35CA; and
0TJ+100C for the LM35D. VS = +5Vdc and ILOAD = 50 A, in the circuit of Figure 2. These specifications also apply from +2C to TMAX in the circuit of Figure 1.
Specifications in boldface apply over the full rated temperature range.
Note 2: Thermal resistance of the TO-46 package is 400C/W, junction to ambient, and 24C/W junction to case. Thermal resistance of the TO-92 package is
180C/W junction to ambient. Thermal resistance of the small outline molded package is 220C/W junction to ambient. Thermal resistance of the TO-220 package
is 90C/W junction to ambient. For additional thermal resistance information see table in the Applications section.
Note 3: Regulation is measured at constant junction temperature, using pulse testing with a low duty cycle. Changes in output due to heating effects can be computed by multiplying the internal dissipation by the thermal resistance.
Note 4: Tested Limits are guaranteed and 100% tested in production.
Note 5: Design Limits are guaranteed (but not 100% production tested) over the indicated temperature and supply voltage ranges. These limits are not used to calculate outgoing quality levels.
Note 6: Specifications in boldface apply over the full rated temperature range.
Note 7: Accuracy is defined as the error between the output voltage and 10mv/C times the devices case temperature, at specified conditions of voltage, current,
and temperature (expressed in C).
Note 8: Nonlinearity is defined as the deviation of the output-voltage-versus-temperature curve from the best-fit straight line, over the devices rated temperature
range.
Note 9: Quiescent current is defined in the circuit of Figure 1.
Note 10: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. DC and AC electrical specifications do not apply when operating
the device beyond its rated operating conditions. See Note 1.
Note 11: Human body model, 100 pF discharged through a 1.5 k resistor.
Note 12: See AN-450 Surface Mounting Methods and Their Effect on Product Reliability or the section titled Surface Mount found in a current National Semiconductor Linear Data Book for other methods of soldering surface mount devices.

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Typical Performance Characteristics

Thermal Resistance
Junction to Air

Thermal Response
in Still Air

Thermal Time Constant

DS005516-26
DS005516-25

Thermal Response in
Stirred Oil Bath

DS005516-27

Minimum Supply
Voltage vs. Temperature

Quiescent Current
vs. Temperature
(In Circuit of Figure 1.)

DS005516-29

DS005516-28

DS005516-30

Quiescent Current
vs. Temperature
(In Circuit of Figure 2.)

Accuracy vs. Temperature

(Guaranteed)

Accuracy vs. Temperature

(Guaranteed)

DS005516-32

DS005516-33

DS005516-31

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Typical Performance Characteristics

(Continued)

Noise Voltage

Start-Up Response

DS005516-34

DS005516-35

The TO-46 metal package can also be soldered to a metal

surface or pipe without damage. Of course, in that case the
V terminal of the circuit will be grounded to that metal. Alternatively, the LM35 can be mounted inside a sealed-end
metal tube, and can then be dipped into a bath or screwed
into a threaded hole in a tank. As with any IC, the LM35 and
accompanying wiring and circuits must be kept insulated and
dry, to avoid leakage and corrosion. This is especially true if
the circuit may operate at cold temperatures where condensation can occur. Printed-circuit coatings and varnishes such
as Humiseal and epoxy paints or dips are often used to insure that moisture cannot corrode the LM35 or its connections.
These devices are sometimes soldered to a small
light-weight heat fin, to decrease the thermal time constant
and speed up the response in slowly-moving air. On the
other hand, a small thermal mass may be added to the sensor, to give the steadiest reading despite small deviations in
the air temperature.

Applications
The LM35 can be applied easily in the same way as other
integrated-circuit temperature sensors. It can be glued or cemented to a surface and its temperature will be within about
0.01C of the surface temperature.
This presumes that the ambient air temperature is almost the
same as the surface temperature; if the air temperature were
much higher or lower than the surface temperature, the actual temperature of the LM35 die would be at an intermediate
temperature between the surface temperature and the air
temperature. This is expecially true for the TO-92 plastic
package, where the copper leads are the principal thermal
path to carry heat into the device, so its temperature might
be closer to the air temperature than to the surface temperature.
To minimize this problem, be sure that the wiring to the
LM35, as it leaves the device, is held at the same temperature as the surface of interest. The easiest way to do this is
to cover up these wires with a bead of epoxy which will insure that the leads and wires are all at the same temperature
as the surface, and that the LM35 dies temperature will not
be affected by the air temperature.

Temperature Rise of LM35 Due To Self-heating (Thermal Resistance,JA)

TO-46,

TO-46*,

TO-92,

TO-92**,

SO-8

SO-8**

TO-220

no heat
sink

small heat fin

no heat
sink

small heat fin

no heat
sink

small heat fin

no heat
sink

Still air

400C/W

100C/W

180C/W

140C/W

220C/W

110C/W

90C/W

Moving air

100C/W

40C/W

90C/W

70C/W

105C/W

90C/W

26C/W

Still oil

100C/W

40C/W

90C/W

70C/W

Stirred oil

50C/W

30C/W

45C/W

40C/W

(Clamped to metal,
Infinite heat sink)

(24C/W)

(55C/W)

*Wakefield type 201, or 1" disc of 0.020" sheet brass, soldered to case, or similar.
**TO-92 and SO-8 packages glued and leads soldered to 1" square of 1/16" printed circuit board with 2 oz. foil or similar.

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Typical Applications

DS005516-19

FIGURE 3. LM35 with Decoupling from Capacitive Load

DS005516-6

FIGURE 6. Two-Wire Remote Temperature Sensor

(Output Referred to Ground)
DS005516-20

FIGURE 4. LM35 with R-C Damper

CAPACITIVE LOADS
Like most micropower circuits, the LM35 has a limited ability
to drive heavy capacitive loads. The LM35 by itself is able to
drive 50 pf without special precautions. If heavier loads are
anticipated, it is easy to isolate or decouple the load with a
resistor; see Figure 3. Or you can improve the tolerance of
capacitance with a series R-C damper from output to
ground; see Figure 4.
When the LM35 is applied with a 200 load resistor as
shown in Figure 5, Figure 6 or Figure 8 it is relatively immune
to wiring capacitance because the capacitance forms a bypass from ground to input, not on the output. However, as
with any linear circuit connected to wires in a hostile environment, its performance can be affected adversely by intense
electromagnetic sources such as relays, radio transmitters,
motors with arcing brushes, SCR transients, etc, as its wiring
can act as a receiving antenna and its internal junctions can
act as rectifiers. For best results in such cases, a bypass capacitor from VIN to ground and a series R-C damper such as
75 in series with 0.2 or 1 F from output to ground are often
useful. These are shown in Figure 13, Figure 14, and
Figure 16.

DS005516-7

FIGURE 7. Temperature Sensor, Single Supply, 55 to

+150C

DS005516-8

FIGURE 8. Two-Wire Remote Temperature Sensor

(Output Referred to Ground)

DS005516-5

FIGURE 5. Two-Wire Remote Temperature Sensor

(Grounded Sensor)

DS005516-9

FIGURE 9. 4-To-20 mA Current Source (0C to +100C)

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Typical Applications

(Continued)

DS005516-11

FIGURE 11. Centigrade Thermometer (Analog Meter)

DS005516-10

FIGURE 10. Fahrenheit Thermometer

DS005516-12

FIGURE 12. Fahrenheit ThermometerExpanded Scale

Thermometer
(50 to 80 Fahrenheit, for Example Shown)

DS005516-13

FIGURE 13. Temperature To Digital Converter (Serial Output) (+128C Full Scale)

DS005516-14

FIGURE 14. Temperature To Digital Converter (Parallel TRI-STATE Outputs for

Standard Data Bus to P Interface) (128C Full Scale)

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Typical Applications

(Continued)

DS005516-16

* = 1% or 2% film resistor

Trim RB for VB = 3.075V

Trim RC for VC = 1.955V
Trim RA for VA = 0.075V + 100mV/C x Tambient
Example, VA = 2.275V at 22C

FIGURE 15. Bar-Graph Temperature Display (Dot Mode)

DS005516-15

FIGURE 16. LM35 With Voltage-To-Frequency Converter And Isolated Output

(2C to +150C; 20 Hz to 1500 Hz)

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Block Diagram

DS005516-23

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10

Physical Dimensions

inches (millimeters) unless otherwise noted

TO-46 Metal Can Package (H)

Order Number LM35H, LM35AH, LM35CH,
LM35CAH, or LM35DH
NS Package Number H03H

SO-8 Molded Small Outline Package (M)

Order Number LM35DM
NS Package Number M08A

11

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Physical Dimensions

inches (millimeters) unless otherwise noted (Continued)

Power Package TO-220 (T)

Order Number LM35DT
NS Package Number TA03F

TO-92 Plastic Package (Z)

Order Number LM35CZ, LM35CAZ or LM35DZ
NS Package Number Z03A

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12

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LM35/LM35A/LM35C/LM35CA/LM35D Precision Centigrade Temperature Sensors

Notes