LM45BIM3 [NSC]
SOT-23 Precision Centigrade Temperature Sensors; SOT- 23精密摄氏温度传感器
| 型号： | LM45BIM3 |
| 厂家： | 
National Semiconductor |
| 描述： | SOT-23 Precision Centigrade Temperature Sensors |
| 文件： | 总9页 (文件大小：218K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
July 1999
LM45
SOT-23 Precision Centigrade Temperature Sensors
n Portable Medical Instruments
n HVAC
The LM45 series are precision integrated-circuit temperature
n Power Supply Modules
General Description
sensors, whose output voltage is linearly proportional to the
Celsius (Centigrade) temperature. The LM45 does not re-
quire any external calibration or trimming to provide accura-
n Disk Drives
n Computers
n Automotive
±
±
cies of 2˚C at room temperature and 3˚C over a full −20 to
+100˚C temperature range. Low cost is assured by trimming
and calibration at the wafer level. The LM45’s low output im-
pedance, linear output, and precise inherent calibration
make interfacing to readout or control circuitry especially
easy. It can be used with a single power supply, or with plus
and minus supplies. As it draws only 120 µA from its supply,
it has very low self-heating, less than 0.2˚C in still air. The
LM45 is rated to operate over a −20˚ to +100˚C temperature
range.
Features
n Calibrated directly in ˚ Celsius (Centigrade)
n Linear + 10.0 mV/˚C scale factor
±
n
3˚C accuracy guaranteed
n Rated for full −20˚ to +100˚C range
n Suitable for remote applications
n Low cost due to wafer-level trimming
n Operates from 4.0V to 10V
n Less than 120 µA current drain
n Low self-heating, 0.20˚C in still air
Applications
n Battery Management
n FAX Machines
n Printers
±
n Nonlinearity only 0.8˚C max over temp
n Low impedance output, 20Ω for 1 mA load
Connection Diagram
SOT-23
Order
Device
Marking
T4B
SOT-23
Number
Supplied As
LM45BIM3
LM45BIM3X
LM45CIM3
LM45CIM3X
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
T4B
T4C
T4C
DS011754-1
Top View
See NS Package Number MA03B
Typical Applications
DS011754-3
DS011754-4
FIGURE 1. Basic Centigrade Temperature
Sensor (+2.5˚C to +100˚C)
=
Choose R
−V /50 µA
S
1
=
V
OUT
V
OUT
(10 mV/˚C x Temp ˚C)
+1,000 mV at +100˚C
=
=
=
+250 mV at +25˚C
−200 mV at −20˚C
FIGURE 2. Full-Range Centigrade
Temperature Sensor (−20˚C to +100˚C)
© 1999 National Semiconductor Corporation
DS011754
www.national.com
Absolute Maximum Ratings (Note 1)
Operating Ratings (Note 1)
Specified Temperature Range
(Note 4)
Supply Voltage
Output Voltage
+12V to −0.2V
T
to TMAX
+V + 0.6V to
S
MIN
−1.0V
LM45B, LM45C
−20˚C to +100˚C
Output Current
10 mA
Operating Temperature Range
LM45B, LM45C
Storage Temperature
Lead Temperature:
−65˚C to +150˚C
−40˚C to +125˚C
+4.0V to +10V
Supply Voltage Range (+VS)
SOT Package (Note 2):
Vapor Phase (60 seconds)
Infrared (15 seconds)
215˚C
220˚C
ESD Susceptibility (Note 3):
Human Body Model
Machine Model
2000V
250V
Electrical Characteristics
=
=
Unless otherwise noted, these specifications apply for +VS +5Vdc and ILOAD +50 µA, in the circuit of Figure 2. These
=
=
=
J
specifications also apply from +2.5˚C to TMAX in the circuit of Figure 1 for +VS +5Vdc. Boldface limits apply for TA
T
=
=
TMIN to TMAX ; all other limits TA TJ +25˚C, unless otherwise noted.
Parameter Conditions
LM45B
Typical Limit
(Note 5)
LM45C
Typical Limit
(Note 5)
Units
(Limit)
=
±
±
±
±
±
±
±
±
Accuracy
(Note 6)
T A +25˚C
2.0
3.0
3.0
0.8
3.0
4.0
4.0
0.8
˚C (max)
˚C (max)
˚C (max)
˚C (max)
=
T A TMAX
=
T A TMIN
Nonlinearity
(Note 7)
T
T
MIN≤TA≤TMAX
Sensor Gain
MIN≤TA≤TMAX
+9.7
+9.7
mV/˚C (min)
mV/˚C (max)
(Average Slope)
+10.3
+10.3
±
±
35
Load Regulation (Note 8)
0≤I L≤ +1 mA
35
mV/mA
(max)
±
±
0.80
Line Regulation
+4.0V≤+V S≤+10V
0.80
mV/V (max)
mV/V (max)
µA (max)
±
±
1.2
(Note 8)
1.2
Quiescent Current
(Note 9)
+4.0V≤+V S≤+10V, +25˚C
+4.0V≤+V S≤+10V
4.0V≤+V S≤10V
120
160
2.0
120
160
2.0
µA (max)
Change of Quiescent
Current (Note 9)
µA (max)
Temperature Coefficient
of Quiescent Current
Minimum Temperature
for Rated Accuracy
Long Term Stability (Note 10)
+2.0
+2.0
µA/˚C
˚C (min)
˚C
In circuit of
+2.5
+2.5
=
Figure 1, IL
=
0
±
±
0.12
T
TMAX, for 1000 hours
0.12
J
Note 1: 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.
Note 2: See AN-450 “Surface Mounting Methods and Their Effect on Product Reliability” or the section titled “Surface Mount” found in a current National Semicon-
ductor Linear Data Book for other methods of soldering surface mount devices.
Note 3: Human body model, 100 pF discharged through a 1.5 kΩ resistor. Machine model, 200 pF discharged directly into each pin.
Note 4: Thermal resistance of the SOT-23 package is 260˚C/W, junction to ambient when attached to a printed circuit board with 2 oz. foil as shown in Figure 3.
Note 5: Limits are guaranteed to National’s AOQL (Average Outgoing Quality Level).
Note 6: Accuracy is defined as the error between the output voltage and 10 mv/˚C times the device’s case temperature, at specified conditions of voltage, current,
and temperature (expressed in ˚C).
Note 7: 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 8: 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 9: Quiescent current is measured using the circuit of Figure 1.
Note 10: 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.
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2
Typical Performance Characteristics To generate these curves the LM45 was mounted to a printed
circuit board as shown in Figure 3.
Thermal Resistance
Junction to Air
Thermal Response in Still Air
with Heat Sink (Figure 3)
Thermal Time Constant
DS011754-24
DS011754-25
DS011754-26
Thermal Response
in Stirred Oil Bath
with Heat Sink
Quiescent Current
vs Temperature
(In Circuit of Figure 1)
Start-Up Voltage
vs Temperature
DS011754-27
DS011754-28
DS011754-29
Quiescent Current
vs Temperature
(In Circuit of Figure 2)
Accuracy vs Temperature
(Guaranteed)
Noise Voltage
DS011754-30
DS011754-31
DS011754-32
3
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Typical Performance Characteristics To generate these curves the LM45 was mounted to a printed
circuit board as shown in Figure 3. (Continued)
Supply Voltage
vs Supply Current
Start-Up Response
DS011754-34
DS011754-33
DS011754-23
FIGURE 3. Printed Circuit Board Used for Heat Sink to Generate All Curves.
1
⁄2
" Square Printed Circuit Board with 2 oz. Foil or Similar
as Humiseal and epoxy paints or dips are often used to in-
sure that moisture cannot corrode the LM45 or its connec-
tions.
Applications
The LM45 can be applied easily in the same way as other
integrated-circuit temperature sensors. It can be glued or ce-
mented to a surface and its temperature will be within about
0.2˚C of the surface temperature.
Temperature Rise of LM45 Due to Self-Heating
(Thermal Resistance)
SOT-23
SOT-23
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 ac-
tual temperature of the LM45 die would be at an intermediate
temperature between the surface temperature and the air
temperature.
*
**
no heat sink
small heat fin
Still air
450˚C/W
260˚C/W
180˚C/W
Moving air
*
Part soldered to 30 gauge wire.
1
*
*
Heat sink used is
⁄
2
” square printed circuit board with 2 oz. foil with part at-
To ensure good thermal conductivity the backside of the
LM45 die is directly attached to the GND pin. The lands and
traces to the LM45 will, of course, be part of the printed cir-
cuit board, which is the object whose temperature is being
measured. These printed circuit board lands and traces will
not cause the LM45s temperature to deviate from the de-
sired temperature.
tached as shown in Figure 3.
Alternatively, the LM45 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 LM45 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 conden-
sation can occur. Printed-circuit coatings and varnishes such
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4
Typical Applications
CAPACITIVE LOADS
Like most micropower circuits, the LM45 has a limited ability
to drive heavy capacitive loads. The LM45 by itself is able to
drive 500 pF without special precautions. If heavier loads are
anticipated, it is easy to isolate or decouple the load with a
resistor; see Figure 4. Or you can improve the tolerance of
capacitance with
a series R-C damper from output to
ground; see Figure 5.
Any linear circuit connected to wires in a hostile environment
can have its performance affected adversely by intense elec-
tromagnetic sources such as relays, radio transmitters, mo-
tors 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 ca-
pacitor from VIN to ground and a series R-C damper such as
75Ω in series with 0.2 or 1 µF from output to ground, as
shown in Figure 5, are often useful.
DS011754-14
FIGURE 7. 4-to-20 mA Current Source (0˚C to +100˚C)
DS011754-8
FIGURE 4. LM45 with Decoupling from Capacitive Load
DS011754-9
FIGURE 5. LM45 with R-C Damper
DS011754-15
FIGURE 8. Fahrenheit Thermometer
DS011754-12
FIGURE 6. Temperature Sensor,
Single Supply, −20˚C to +100˚C
DS011754-16
FIGURE 9. Centigrade Thermometer (Analog Meter)
5
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Typical Applications (Continued)
DS011754-17
FIGURE 10. Expanded Scale Thermometer
(50˚ to 80˚ Fahrenheit, for Example Shown)
DS011754-18
FIGURE 11. Temperature To Digital Converter (Serial Output) (+128˚C Full Scale)
DS011754-19
®
FIGURE 12. Temperature To Digital Converter (Parallel TRI-STATE Outputs for
Standard Data Bus to µP Interface) (128˚C Full Scale)
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6
Typical Applications (Continued)
DS011754-20
=
*
1% or 2% film resistor
=
-Trim R for V 3.075V
B
B
=
-Trim R for V 1.955V
C
C
=
-Trim R for V 0.075V + 100mV/˚C x T
ambient
A
A
=
-Example, V 2.275V at 22˚C
A
FIGURE 13. Bar-Graph Temperature Display (Dot Mode)
DS011754-21
FIGURE 14. LM45 With Voltage-To-Frequency Converter And Isolated Output
(2.5˚C to +100˚C; 25 Hz to 1000 Hz)
7
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Block Diagram
DS011754-22
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8
Physical Dimensions inches (millimeters) unless otherwise noted
SOT-23 Molded Small Outline Transistor Package (M3)
Order Number LM45BIM3, LM45BIM3X, LM45CIM3 or LM45CIM3X
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
labeling, can be reasonably expected to result in a
significant injury to the user.
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.
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Tel: 1-800-272-9959
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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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