NSC LM62CIM3X 2.7v, 15.6 mv/â°c sot-23 temperature sensor Datasheet

LM62
2.7V, 15.6 mV/˚C SOT-23 Temperature Sensor
General Description
Applications
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 at room temperature and +2.5˚C/
−2.0˚C over the full 0˚C to +90˚C temperature range.
The LM62’s linear output, +480 mV offset, and factory calibration 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.
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Features
Cellular Phones
Computers
Power Supply Modules
Battery Management
FAX Machines
Printers
HVAC
Disk Drives
Appliances
Key Specifications
n Accuracy at 25˚C
± 2.0 or ± 3.0˚C
(max)
n Temperature Slope
n Power Supply Voltage Range
+15.6 mV/˚C
+2.7V to +10V
n Current Drain @ 25˚C
130 µA (max)
n Nonlinearity
± 0.8˚C (max)
n Output Impedance
4.7 kΩ (max)
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
Typical Application
SOT-23
DS100893-1
Top View
See NS Package Number MA03B
Ordering Information
Order
SOT-23
Number
Device
Supplied As
DS100893-2
VO = (+15.6 mV/˚C x T˚C) + 480 mV
Temperature (T)
Typical VO
+90˚C
+1884 mV
+70˚C
+1572 mV
Marking
+25˚C
870 mV
LM62BIM3
T7B
1000 Units on Tape and Reel
0˚C
+480 mV
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
FIGURE 1. Full-Range Centigrade Temperature Sensor
(0˚C to +90˚C) Stabilizing a Crystal Oscillator
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LM62 2.7V, 15.6 mV/˚C, SOT-23 Temperature Sensor
June 1999
Absolute Maximum Ratings (Note 1)
Supply Voltage
Output Voltage
Output Current
Input Current at any pin (Note 2)
Storage Temperature
Maximum Junction Temperature (TJMAX)
ESD Susceptibility (Note 3) :
Human Body Model
Machine Model
Lead Temperature:
SOT Package (Note 4) :
Vapor Phase (60 seconds)
Infrared (15 seconds)
+12V to −0.2V
(+VS + 0.6V) to
−0.6V
10 mA
5 mA
−65˚C to +150˚C
+125˚C
+215˚C
+220˚C
Operating Ratings(Note 1)
TMIN ≤ TA ≤ TMAX
0˚C ≤ TA ≤ +90˚C
+2.7V to +10V
450˚C/W
Specified Temperature Range:
LM62B, LM62C
Supply Voltage Range (+VS)
Thermal Resistance, θJA(Note 5)
2500V
250V
Electrical Characteristics
Unless otherwise noted, these specifications apply for +VS = +3.0 VDC. Boldface limits apply for TA = TJ = TMIN to TMAX ; all
other limits TA = TJ = 25˚C.
Parameter
Conditions
Typical
(Note 6)
(Note 7)
± 3.0
˚C (max)
˚C (max)
± 0.8
± 1.0
˚C (max)
+16.1
+16.3
mV/˚C (max)
+15.1
+14.9
mV/˚C (min)
+3.0V ≤ +VS ≤ +10V
4.7
4.7
kΩ (max)
0˚C ≤ TA ≤ +75˚C, +VS = +2.7V
4.4
4.4
kΩ (max)
± 1.13
± 9.7
± 1.13
± 9.7
mV/V (max)
130
130
µA (max)
165
165
µA (max)
+480
Sensor Gain
+16
(Average Slope)
+3.0V ≤ +VS ≤ +10V
+2.7V ≤ +VS ≤ +3.3V, 0˚C ≤ TA ≤ +75˚C
Change of Quiescent Current
(Note 7)
Units
(Limit)
+4.0/−3.0
Nonlinearity (Note 9)
Quiescent Current
Limits
+2.5/−2.0
Output Voltage at 0˚C
Line Regulation (Note 10)
LM62C
Limits
± 2.0
Accuracy (Note 8)
Output Impedance
LM62B
+2.7V ≤ +VS ≤ +10V
82
+2.7V ≤ +VS ≤ +10V
Temperature Coefficient of
mV
mV (max)
±5
µA
0.2
µA/˚C
± 0.2
˚C
Quiescent Current
Long Term Stability (Note 11)
TJ = TMAX = +100˚C,
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 (VI) at any pin exceeds power supplies (VI < GND or VI > +VS), the current at that pin should be limited to 5 mA.
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 (θJA) is specified without a heat sink in still air.
Note 6: Typicals are at TJ = TA = 25˚C and represent most likely parametric norm.
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.
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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.
Thermal Resistance
Junction to Air
Thermal Time Constant
Thermal Response in
Still Air with Heat Sink
DS100893-3
Thermal Response
in Stirred Oil Bath
with Heat Sink
DS100893-4
DS100893-5
Thermal Response in Still
Air without a Heat Sink
DS100893-6
Quiescent Current
vs. Temperature
DS100893-8
Accuracy vs Temperature
Noise Voltage
DS100893-10
DS100893-9
3
DS100893-11
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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
DS100893-22
DS100893-12
DS100893-14
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.
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 (θJA) is the parameter 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:
TJ = TA + θJA [(+VS IQ) + (+VS − VO) IL]
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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where IQ is the quiescent current and ILis the load current on
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.
4
1.0 Mounting
0.1 µF be added from +VS to GND to bypass the power supply voltage, as shown in 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.
(Continued)
The table shown in Figure 3 summarizes the rise in die temperature of the LM62 without any loading, and the thermal
resistance for different conditions.
SOT-23
SOT-23
no heat sink
small heat fin
(Note 13)
Still air
(Note 12)
θJA
TJ − TA
θJA
TJ − TA
(˚C/W)
(˚C)
(˚C/W)
(˚C)
450
0.17
260
0.1
180
0.07
Moving
air
DS100893-15
Note 12: Heat sink used is 1⁄2" square printed circuit board with 2 oz. foil with
part attached as shown in Figure 2 .
FIGURE 4. LM62 No Decoupling Required for
Capacitive Load
Note 13: Part soldered to 30 gauge wire.
FIGURE 3. Temperature Rise of LM62 Due to
Self-Heating and Thermal Resistance (θJA)
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. Over the specified temperature range the
LM62 has a maximum output impedance of 4.7 kΩ. In an extremely noisy environment it may be necessary to add some
filtering to minimize noise pickup. It is recommended that
DS100893-16
FIGURE 5. LM62 with Filter for Noisy Environment
DS100893-17
FIGURE 6. Simplified Schematic
5
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3.0 Applications Circuits
DS100893-18
FIGURE 7. Centigrade Thermostat
DS100893-19
FIGURE 8. Conserving Power Dissipation with Shutdown
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LM62 2.7V, 15.6 mV/˚C, SOT-23 Temperature Sensor
Physical Dimensions
inches (millimeters) unless otherwise noted
SOT-23 Molded Small Outline Transistor Package (M3)
Order Number LM62BIM3 or LM62CIM3
NS Package Number MA03B
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