Datasheet LM61CIZ, LM61CIM3, LM61BIM3, LM61BIZ Datasheet (NSC)

LM61

2.7V, SOT-23 or TO-92 Temperature Sensor

LM61 2.7V, SOT-23 or TO-92 Temperature Sensor

June 1999

General Description

The LM61 is a precision integrated-circuit temperature sen­sor that can sense a −30˚C to +100˚C temperature range
while operating from a single +2.7V supply.The LM61’s out­put voltage is linearly proportional to Celsius (Centigrade)
temperature (+10 mV/˚C) and has a DC offset of +600mV.
The offset allows reading negative temperatures without the
need for a negative supply.The nominal output voltage of the
LM61 ranges from +300 mV to +1600 mV for a −30˚C to
+100˚C temperature range. The LM61 is calibrated to pro­vide accuracies of
over the full −25˚C to +85˚C temperature range.

The LM61’s linear output, +600mV offset, and factory cali­bration simplify external circuitry required in a single supply
environment where reading negative temperatures is re­quired. Because the LM61’s quiescent current is less than
125 µA, self-heating is limited to a very low 0.2˚C in still air.
Shutdown capability for the LM61 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±3˚C

Features

n Calibrated linear scale factor of +10 mV/˚C
n Rated for full −30˚ to +100˚C range
n Suitable for remote applications

Typical Application

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 Accuracy for −30˚C to +100˚C
n Accuracy for −25˚C to +85˚C
n Temperature Slope +10 mV/˚C
n Power Supply Voltage Range +2.7V to +10V
n Current Drain
n Nonlinearity
n Output Impedance 800 Ω (max)

@

25˚C 125 µA (max)

±

2.0 or±3.0˚C
(max)

±

4.0˚C (max)

±

3.0˚C (max)

±

0.8˚C (max)

DS012897-2

=

V

(+10 mV/˚C x T ˚C) + 600 mV

O

Temperature (T) Typical V

+100˚C +1600 mV

+85˚C +1450 mV
+25˚C +850 mV

0˚C +600 mV

−25˚C +350 mV

−30˚C +300 mV

FIGURE 1. Full-Range Centigrade Temperature Sensor (−30˚C to +100˚C)

Operating from a Single Li-Ion Battery Cell

© 1999 National Semiconductor Corporation DS012897 www.national.com

O

Connection Diagrams

SOT-23

DS012897-1

See NS Package Number MA03B

Top View

Ordering Information

Order

Number

LM61BIM3 T1B 1000 Units on Tape and Reel
LM61BIM3X T1B 3000 Units on Tape and Reel
LM61CIM3 T1C 1000 Units on Tape and Reel
LM61CIM3X T1C 3000 Units on Tape and Reel
LM61BIZ LM61BIZ Bulk
LM61CIZ LM61CIZ Bulk

Device

Marking

Supplied In

See NS Package Number Z03A

Accuracy

Over

Specified

Temperature

Range (˚C)

±

3 −25˚C to +85˚C

±

4 −30˚C to +100˚C

±

3 −25˚C to +85˚C

±

4 −30˚C to +100˚C

TO-92

DS012897-25

Top View

Specified

Temperature

Range

Package

Type

SOT-23

TO-92

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Absolute Maximum Ratings (Note 1)

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

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

) +125˚C

(T

JMAX

ESD Susceptibility (Note 3) :

Human Body Model 2500V
Machine Model 250V

+ 0.6V) to

S

−0.6V

Lead Temperature:

TO-92 Package:

Soldering (10 seconds) +260˚C

SOT-23 Package (Note 4):

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

Operating Ratings(Note 1)

Specified Temperature Range: T

LM61C −30˚C ≤ TA≤ +100˚C

LM61B −25˚C ≤ T
Supply Voltage Range (+V
Thermal Resistance, θ

SOT-23

TO-92

) +2.7V to +10V

S

(Note 5)

JA

MIN

≤ TA≤ T

≤ +85˚C

A

450˚C/W
180˚C/W

MAX

Electrical Characteristics

Unless otherwise noted, these specifications apply for +V
other limits T

=

=

T

25˚C.

A

J

Parameter Conditions Typical

=

S

. Boldface limits apply for T

+3.0 V

DC

(Note 6)

LM61B LM61C Units

Limits Limits

(Note 7) (Note 7)

Accuracy (Note 8)

±

±

Output Voltage at 0˚C +600 mV
Nonlinearity (Note 9)
Sensor Gain +10 +9.7 +9.6 mV/˚C (min)
(Average Slope) +10.3 +10.4 mV/˚C (max)
Output Impedance +3.0V ≤ +V

−30˚C ≤ T
+85˚C ≤ T

Line Regulation (Note 10) +3.0V ≤ +V

+2.7V ≤ +V

Quiescent Current +2.7V ≤ +V

Change of Quiescent Current +2.7V ≤ +V

≤ +10V

S

≤ +85˚C, +V

A

≤ +100˚C, +V

A

≤ +10V

S

≤ +3.3V

S

≤ +10V 82 125 125 µA (max)

S

≤ +10V

S

S

=

=

S

+2.7V

+2.7V

±

5µA
Temperature Coefficient of 0.2 µA/˚C
Quiescent Current

=

Long Term Stability (Note 11) T

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 di-

rectly 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 Semi-

conductor 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 +10 mV/˚C times the device’s case temperature plus 600 mV,at specified conditions of volt-

age, 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 com-

puted 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

=

=

T

25˚C and represent most likely parametric norm.

J

A

=

T

+100˚C,

J

MAX

for 1000 hours

JA

<

I

) is specified without a heat sink in still air.

GND or V

>

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

I

±

0.2 ˚C

±

0.8

2.3

±
±

155 155 µA (max)

2.0

3.0

0.6

5

0.7

5.7

=

=

T

A

T

J

MIN

±

3.0 ˚C (max)

±

4.0 ˚C (max)

±

0.8 ˚C (max)

0.8

2.3
5

±

0.7 mV/V (max)

±

5.7 mV (max)

to T

MAX

(Limit)

kΩ (max)
kΩ (max)
kΩ (max)

; all

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Typical PerformanceCharacteristics The LM61 in the SOT-23 package mounted to a printed circuit

board as shown in

Figure 2

was used to generate the following thermal curves.

Thermal Resistance
Junction to Air

Thermal Response
in Stirred Oil Bath
with Heat Sink

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Thermal Time Constant

Thermal Response in Still
Air without a Heat Sink

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Thermal Response in
Still Air with Heat Sink

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Quiescent Current
vs. Temperature

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Accuracy vs Temperature

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Noise Voltage

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Typical Performance Characteristics The LM61 in the SOT-23 package mounted to a printed

circuit board as shown in

Figure 2

was used to generate the following thermal curves. (Continued)

Supply Voltage
vs Supply Current

Start-Up Response

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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 LM61 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 LM61 is sens­ing will be within about +0.2˚C of the surface temperature
that LM61’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
LM61 die is directly attached to the GND pin. The lands and
traces to the LM61 will, of course, be part of the printed cir­cuit board, which is the object whose temperature is being
measured.

Alternatively, the LM61 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 LM61 and

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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 LM61 or its connec­tions.

The thermal resistance junction to ambient (θ
rameter used to calculate the rise of a device junction tem-

) is the pa-

JA

perature due to its power dissipation. For the LM61 the
equation used to calculate the rise in the die temperature is
as follows:

=

T

+ θJA[(+VSIQ) + (+VS−VO)IL]

T

J

A

is the quiescent current and ILis the load current on

where I

Q

the output. Since the LM61’s junction temperature is the ac­tual temperature being measured care should be taken to
minimize the load current that the LM61 is required to drive.

The table shown in

Figure 3

summarizes the rise in die tem­perature of the LM61 without any loading with a 3.3V supply,
and the thermal resistance for different conditions.

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1.0 Mounting (Continued)

SOT-23* SOT-23** TO-92* TO-92***

no heat sink small heat fin no heat sink small heat fin

θ

(˚C/W) (˚C) (˚C/W) (˚C) (˚C/W) (˚C) (˚C/W) (˚C)

Still air 450 0.26 260 0.13 180 0.09 140 0.07
Moving air 180 0.09 90 0.05 70 0.03

TJ−T

JA

θ

A

TJ−T

JA

θ

A

TJ−T

JA

θ

A

TJ−T

JA

A

*Part soldered to 30 gauge wire.
**Heat sink used is

1

⁄2" square printed circuit board with 2 oz. foil with part attached as shown in

***Part glued and leads soldered to 1″ square of 1/16″ printed circuit board with 2oz. foil or similar.

FIGURE 3. Temperature Rise of LM61 Due to

Self-Heating and Thermal Resistance (θ

)

JA

2.0 Capacitive Loads

The LM61 handles capacitive loading well. Without any spe­cial precautions, the LM61 can drive any capacitive load as
shown in

Figure 4

LM61 has a maximum output impedance of 5 kΩ.Inanex­tremely noisy environment it may be necessary to add some
filtering to minimize noise pickup. It is recommended that

0.1 µF be added from +V
ply voltage, as shown in
may be necessary to add a capacitor from the output to
ground. A 1 µF output capacitor with the 5 kΩ maximum out­put impedance will form a 32 Hz lowpass filter. Since the
thermal time constant of the LM61 is much slower than the 5
ms time constant formed by the RC, the overall response
time of the LM61 will not be significantly affected. For much
larger capacitors this additional time lag will increase the
overall response time of the LM61.

. Over the specified temperature range the

to GND to bypass the power sup-

S

Figure 5

. In a noisy environment it

FIGURE 4. LM61 No Decoupling Required for

Capacitive Load

FIGURE 5. LM61 with Filter for Noisy Environment

Figure 2

.

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FIGURE 6. Simplified Schematic

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3.0 Applications Circuits

FIGURE 7. Centigrade Thermostat

FIGURE 8. Conserving Power Dissipation with Shutdown

4.0 Recommended Solder Pads for SOT-23 Package

DS012897-18

DS012897-19

DS012897-20

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Physical Dimensions inches (millimeters) unless otherwise noted

SOT-23 Molded Small Outline Transistor Package (M3)

Order Number LM61BIM3 or LM61CIM3

NS Package Number MA03B

TO-92 Plastic Package (Z)

Order Number LM61BIZ or LM61CIZ

NS Package Number Z03A

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Notes

LM61 2.7V, SOT-23 or TO-92 Temperature Sensor

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.

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