Rainbow Electronics LM62 User Manual

LM62

2.7V, 15.6 mV/˚C SOT-23 Temperature Sensor

General Description

The LM62 is a precision integrated-circuit temperature sen­sor that can sense a 0˚C to +90˚C temperature range while
operating from a single +3.0V supply. The LM62’s output
voltage is linearly proportional to Celsius (Centigrade) tem­perature (+15.6 mV/˚C) and has a DC offset of +480 mV.
The offset allows reading temperatures down to 0˚C without
the needforanegative supply.The nominal output voltage of
the LM62 ranges from +480 mV to +1884 mV for a 0˚C to
+90˚C temperature range. The LM62 is calibrated to provide
accuracies of

−2.0˚C over the full 0˚C to +90˚C temperature range.
The LM62’s linear output, +480 mV offset, and factory cali-

bration simplify external circuitry required in a single supply
environment where reading temperatures down to 0˚C is
required. Because the LM62’s quiescent current is less than
130 µA, self-heating is limited to a very low 0.2˚C in still air.
Shutdown capability for the LM62 is intrinsic because its
inherent low power consumption allows it to be powered
directly from the output of many logic gates.

±

2.0˚C at room temperature and +2.5˚C/

Features

n Calibrated linear scale factor of +15.6 mV/˚C

n Rated for full 0˚C to +90˚C range with 3.0V supply
n Suitable for remote applications

Applications

n Cellular Phones
n Computers
n Power Supply Modules
n Battery Management
n FAX Machines
n Printers
n HVAC
n Disk Drives
n Appliances

Key Specifications

n Accuracy at 25˚C
n Temperature Slope +15.6 mV/˚C
n Power Supply Voltage Range +2.7V to +10V
n Current Drain
n Nonlinearity
n Output Impedance 4.7 kΩ (max)

@

25˚C 130 µA (max)

June 1999

±

2.0 or±3.0˚C (max)

±

0.8˚C (max)

LM62 2.7V, 15.6 mV/˚C, SOT-23 Temperature Sensor

Connection Diagram

SOT-23

DS100893-1

Top View

See NS Package Number MA03B

Ordering Information

Order SOT-23

Number Device Supplied As

Marking

LM62BIM3 T7B 1000 Units on Tape and Reel
LM62BIM3X T7B 3000 Units on Tape and Reel
LM62CIM3 T7C 1000 Units on Tape and Reel
LM62CIM3X T7C 3000 Units on Tape and Reel

Typical Application

DS100893-2

VO= (+15.6 mV/˚C x T˚C) + 480 mV

Temperature (T) Typical V

+90˚C +1884 mV
+70˚C +1572 mV
+25˚C 870 mV

0˚C +480 mV

FIGURE 1. Full-Range Centigrade Temperature Sensor

(0˚C to +90˚C) Stabilizing a Crystal Oscillator

O

© 2001 National Semiconductor Corporation DS100893 www.national.com

Absolute Maximum Ratings (Note 1)

LM62

Supply Voltage +12V to −0.2V
Output Voltage (+V

+ 0.6V) to

S

−0.6V

Lead Temperature:

SOT Package (Note 4) :

Vapor Phase (60 seconds) +215˚C
Infrared (15 seconds) +220˚C

Output Current 10 mA
Input Current at any pin (Note 2) 5 mA
Storage Temperature −65˚C to +150˚C
Maximum Junction Temperature (T

) +125˚C

JMAX

ESD Susceptibility (Note 3) :

Human Body Model 2500V

Operating Ratings(Note 1)

Specified Temperature Range: T

LM62B, LM62C 0˚C ≤ TA≤ +90˚C
Supply Voltage Range (+V
Thermal Resistance, θ

) +2.7V to +10V

S

(Note 5) 450˚C/W

JA

MIN

≤ TA≤ T

Machine Model 250V

Electrical Characteristics

Unless otherwise noted, these specifications apply for +VS= +3.0 VDC. Boldface limits apply for TA=TJ=T
other limits T

Parameter Conditions Typical

A=TJ

= 25˚C.

(Note 6)

LM62B LM62C Units

Limits Limits

(Note 7) (Note 7)

Accuracy (Note 8)

±

2.0

±

3.0 ˚C (max)

+2.5/−2.0 +4.0/−3.0 ˚C (max)
Output Voltage at 0˚C +480 mV
Nonlinearity (Note 9)

±

0.8

±

1.0 ˚C (max)

Sensor Gain +16 +16.1 +16.3 mV/˚C (max)
(Average Slope) +15.1 +14.9 mV/˚C (min)
Output Impedance +3.0V ≤ +V

0˚C ≤ T

Line Regulation (Note 10) +3.0V ≤ +V

+2.7V ≤ +V

Quiescent Current +2.7V ≤ +V

≤ +10V 4.7 4.7 kΩ (max)

S

≤ +75˚C, +VS= +2.7V 4.4 4.4 kΩ (max)

A

≤ +10V

S

≤ +3.3V, 0˚C ≤ TA≤ +75˚C

S

≤ +10V 82 130 130 µA (max)

S

±

±

1.13

9.7

±

1.13 mV/V (max)

±

9.7 mV (max)

165 165 µA (max)

Change of Quiescent Current +2.7V ≤ +V

≤ +10V

S

±

5µA
Temperature Coefficient of 0.2 µA/˚C
Quiescent Current
Long Term Stability (Note 11) T

for 1000 hours

Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is
functional, but do not guarantee specific performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics. The guaranteed
specifications apply only for the test conditions listed. Some performance characteristics may degrade when the device is not operated under the listed test
conditions.

Note 2: When the input voltage (V
Note 3: The human body model is a 100 pF capacitor discharged through a 1.5 kΩ resistor into each pin. The machine model is a 200 pF capacitor discharged

directly into each pin.
Note 4: See AN-450 “Surface Mounting Methods and Their Effect on Product Reliability” or the section titled “Surface Mount” found in any post 1986 National

Semiconductor Linear Data Book for other methods of soldering surface mount devices.

Note 5: The junction to ambient thermal resistance (θ
Note 6: Typicals are at T
Note 7: Limits are guaranteed to National’s AOQL (Average Outgoing Quality Level).
Note 8: Accuracy is defined as the error between the output voltage and +15.6 mV/˚C times the device’s case temperature plus 480 mV, at specified conditions of

voltage, current, and temperature (expressed in ˚C).
Note 9: Nonlinearity is defined as the deviation of the output-voltage-versus-temperature curve from the best-fit straight line, over the device’s rated temperature

range.
Note 10: 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 11: For best long-term stability, any precision circuit will give best results if the unit is aged at a warm temperature, and/or temperature cycled for at least 46

hours before long-term life test begins. This is especially true when a small (Surface-Mount) part is wave-soldered; allow time for stress relaxation to occur. The
majority of the drift will occur in the first 1000 hours at elevated temperatures. The drift after 1000 hours will not continue at the first 1000 hour rate.

) at any pin exceeds power supplies (V

I

= 25˚C and represent most likely parametric norm.

J=TA

J=TMAX

=+100˚C,

<

GND or V

I

) is specified without a heat sink in still air.

JA

±

0.2 ˚C

>

+VS), the current at that pin should be limited to 5 mA.

I

MIN

to T

MAX

(Limit)

MAX

; all

www.national.com 2

Typical Performance Characteristics To generate these curves the LM62 was mounted to a printed

circuit board as shown in

Figure 2

.

LM62

Thermal Resistance
Junction to Air

Thermal Response
in Stirred Oil Bath
with Heat Sink

DS100893-3

Thermal Time Constant

Thermal Response in Still
Air without a Heat Sink

DS100893-4

Thermal Response in
Still Air with Heat Sink

DS100893-5

Quiescent Current
vs. Temperature

DS100893-6

DS100893-9

Accuracy vs Temperature

DS100893-8

DS100893-10

Noise Voltage

DS100893-11

www.national.com3

Typical Performance Characteristics To generate these curves the LM62 was mounted to a

LM62

printed circuit board as shown in

Figure 2

. (Continued)

Supply Voltage
vs Supply Current

Start-Up Response

DS100893-22

DS100893-12

FIGURE 2. Printed Circuit Board Used

for Heat Sink to Generate All Curves.

1

⁄2" Square Printed Circuit Board

with 2 oz. Copper Foil or Similar.

1.0 Mounting

The LM62 can be applied easily in the same way as other
integrated-circuit temperature sensors. It can be glued or
cemented to a surface. The temperature that the LM62 is
sensing will be within about +0.2˚C of the surface tempera­ture that LM62’s leads are attached to.

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 measured would be at an intermediate
temperature between the surface temperature and the air
temperature.

To ensure good thermal conductivity the backside of the
LM62 die is directly attached to the GND pin. The lands and
traces to the LM62 will, of course, be part of the printed
circuit board, which is the object whose temperature is being
measured. These printed circuit board lands and traces will
not cause the LM62’s temperature to deviate from the de­sired temperature.

DS100893-14

Alternatively, the LM62 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 LM62 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
ensure that moisture cannot corrode the LM62 or its connec­tions.

The thermal resistance junction to ambient (θ

) is the pa-

JA

rameter used to calculate the rise of a device junction tem­perature due to its power dissipation. For the LM62 the
equation used to calculate the rise in the die temperature is
as follows:

T

where I

J=TA+θJA

is the quiescent current and ILis the load current on

Q

[(+VSIQ) + (+VS−VO)IL]

the output. Since the LM62’s junction temperature is the
actual temperature being measured care should be taken to
minimize the load current that the LM62 is required to drive.

www.national.com 4

1.0 Mounting (Continued)

The table shown in
temperature of the LM62 without any loading, and the ther­mal resistance for different conditions.

Still air 450 0.17 260 0.1
Moving

air

Note 12: Heat sink used is1⁄2" square printed circuit board with 2 oz. foil with
part attached as shown in

Note 13: Part soldered to 30 gauge wire.

FIGURE 3. Temperature Rise of LM62 Due to

Self-Heating and Thermal Resistance (θ

Figure 3

summarizes the rise in die

SOT-23 SOT-23

no heat sink small heat fin

(Note 13) (Note 12)

θ

JA

TJ−T

θ

A

JA

TJ−T

(˚C/W) (˚C) (˚C/W) (˚C)

180 0.07

Figure 2

.

)

JA

A

2.0 Capacitive Loads

The LM62 handles capacitive loading well. Without any spe­cial precautions, the LM62 can drive any capacitive load as
shown in
LM62 has a maximum output impedance of 4.7 kΩ.Inan
extremely noisy environment it may be necessary to add
some filtering to minimize noise pickup. It is recommended

Figure 4

. Over the specified temperature range the

that 0.1 µF be added from +V
supply voltage, as shown in

to GND to bypass the power

S

Figure 5

. In a noisy environment
it may be necessary to add a capacitor from the output to
ground. A 1 µF output capacitor with the 4.7 kΩ maximum
output impedance will form a 34 Hz lowpass filter. Since the
thermal time constant of the LM62 is much slower than the
30 ms time constant formed by the RC, the overall response
time of the LM62 will not be significantly affected. For much
larger capacitors this additional time lag will increase the
overall response time of the LM62.

DS100893-15

FIGURE 4. LM62 No Decoupling Required for

Capacitive Load

DS100893-16

FIGURE 5. LM62 with Filter for Noisy Environment

LM62

FIGURE 6. Simplified Schematic

DS100893-17

www.national.com5

3.0 Applications Circuits

LM62

DS100893-18

FIGURE 7. Centigrade Thermostat

DS100893-19

FIGURE 8. Conserving Power Dissipation with Shutdown

www.national.com 6

Physical Dimensions inches (millimeters) unless otherwise noted

LM62 2.7V, 15.6 mV/˚C, SOT-23 Temperature Sensor

SOT-23 Molded Small Outline Transistor Package (M3)

Order Number LM62BIM3 or LM62CIM3

NS Package Number MA03B

LIFE SUPPORT POLICY

NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT
DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL
COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein:

1. Life support devices or systems are devices or
systems which, (a) are intended for surgical implant
into the body, or (b) support or sustain life, and
whose failure to perform when properly used in
accordance with instructions for use provided in the

2. A critical component is any component of a life
support device or system whose failure to perform
can be reasonably expected to cause the failure of
the life support device or system, or to affect its
safety or effectiveness.

labeling, can be reasonably expected to result in a
significant injury to the user.

National Semiconductor
Corporation

Americas
Tel: [phone]
Fax: [phone]
Email: [e-mail]

www.national.com

National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications.

National Semiconductor
Europe

Fax: [phone]

Email: [e-mail]
Deutsch Tel: [phone]
English Tel: [phone]
Français Tel: [phone]

National Semiconductor
Asia Pacific Customer
Response Group

Tel: [phone]
Fax: [phone]
Email: [e-mail]

National Semiconductor
Japan Ltd.

Tel: [phone]
Fax: [phone]