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LM62
2.7V, 15.6 mV/˚C SOT-23 Temperature Sensor
LM62 2.7V, 15.6 mV/˚C, SOT-23 Temperature Sensor
June 1999
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 need for a negative 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, +480mV 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
Connection Diagram
SOT-23
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)
±
2.0 or±3.0˚C
(max)
±
0.8˚C (max)
Typical Application
DS100893-1
See NS Package Number MA03B
Top View
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
© 1999 National Semiconductor Corporation DS100893 www.national.com
=
V
(+15.6 mV/˚C x T˚C) + 480 mV
O
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
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O
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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 (T
) +125˚C
JMAX
ESD Susceptibility (Note 3) :
Human Body Model 2500V
Machine Model 250V
+ 0.6V) to
S
−0.6V
Lead Temperature:
SOT Package (Note 4) :
Vapor Phase (60 seconds) +215˚C
Infrared (15 seconds) +220˚C
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
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)
LM62B LM62C Units
Limits Limits
(Note 7) (Note 7)
Accuracy (Note 8)
±
+2.5/−2.0 +4.0/−3.0 ˚C (max)
Output Voltage at 0˚C +480 mV
Nonlinearity (Note 9)
±
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, +V
A
≤ +10V
S
≤ +3.3V, 0˚C ≤ TA≤ +75˚C
S
≤ +10V 82 130 130 µA (max)
S
=
+2.7V 4.4 4.4 kΩ (max)
S
±
1.13
±
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
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 +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 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
2.0
0.8
9.7
=
=
T
T
A
J
MIN
±
3.0 ˚C (max)
±
1.0 ˚C (max)
±
1.13 mV/V (max)
±
9.7 mV (max)
to T
MAX
(Limit)
; all
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Typical PerformanceCharacteristics To generate these curves the LM62 was mounted to a printed
circuit board as shown in
Figure 2
.
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 To generate these curves the LM62 was mounted to a
printed circuit board as shown in
Figure 2
. (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 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.
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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
rameter used to calculate the rise of a device junction tem-
) is the pa-
JA
perature due to its power dissipation. For the LM62 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 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.
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1.0 Mounting (Continued)
The table shown in
perature 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 tem-
SOT-23 SOT-23
no heat sink small heat fin
(Note 13) (Note 12)
θ
TJ−T
JA
θ
A
TJ−T
JA
(˚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
Figure 4
LM62 has a maximum output impedance of 4.7 kΩ.Inanextremely noisy environment it may be necessary to add some
filtering to minimize noise pickup. It is recommended that
. Over the specified temperature range the
0.1 µF be added from +V
ply voltage, as shown in
to GND to bypass the power sup-
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.
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FIGURE 4. LM62 No Decoupling Required for
Capacitive Load
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FIGURE 5. LM62 with Filter for Noisy Environment
FIGURE 6. Simplified Schematic
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3.0 Applications Circuits
FIGURE 8. Conserving Power Dissipation with Shutdown
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FIGURE 7. Centigrade Thermostat
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Physical Dimensions inches (millimeters) unless otherwise noted
SOT-23 Molded Small Outline Transistor Package (M3)
Order Number LM62BIM3 or LM62CIM3
NS Package Number MA03B
LM62 2.7V, 15.6 mV/˚C, SOT-23 Temperature Sensor
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accordance with instructions for use provided in the
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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.
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Corporation
Americas
Tel: 1-800-272-9959
Fax: 1-800-737-7018
Email: support@nsc.com
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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