Low voltage operation (2.7 V to 5.5 V)
Calibrated directly in °C
10 mV/°C scale factor (20 mV/°C on TMP37)
±2°C accuracy over temperature (typ)
±0.5°C linearity (typ)
Stable with large capacitive loads
Specified −40°C to +125°C, operation to +150°C
Less than 50 µA quiescent current
Shutdown current 0.5 µA max
Low self-heating
Qualified for automotive applications
APPLICATIONS
Environmental control systems
Thermal protection
Industrial process control
Fire alarms
Power system monitors
CPU thermal management
FUNCTIONAL BLOCK DIAGRAM
Figure 1.
PIN CONFIGURATIONS
Figure 2. RJ-5 (SOT-23)
GENERAL DESCRIPTION
The TMP35/TMP36/TMP37 are low voltage, precision centigrade temperature sensors. They provide a voltage output that
is linearly proportional to the Celsius (centigrade) temperature.
The TMP35/TMP36/TMP37 do not require any external
calibration to provide typical accuracies of ±1°C at +25°C
and ±2°C over the −40°C to +125°C temperature range.
The low output impedance of the TMP35/TMP36/TMP37 and
its linear output and precise calibration simplify interfacing to
temperature control circuitry and ADCs. All three devices are
intended for single-supply operation from 2.7 V to 5.5 V maximum. The supply current runs well below 50 µA, providing
very low self-heating—less than 0.1°C in still air. In addition, a
shutdown function is provided to cut the supply current to less
than 0.5 µA.
The TMP35 is functionally compatible with the LM35/LM45
and provides a 250 mV output at 25°C. The TMP35 reads
temperatures from 10°C to 125°C. The TMP36 is specified from
−40°C to +125°C, provides a 750 mV output at 25°C, and
operates to 125°C from a single 2.7 V supply. The TMP36 is
functionally compatible with the LM50. Both the TMP35 and
TMP36 have an output scale factor of 10 mV/°C.
Figure 3. R-8 (SOIC_N)
Figure 4. T-3 (TO-92)
The TMP37 is intended for applications over the range of 5°C
to 100°C and provides an output scale factor of 20 mV/°C. The
TMP37 provides a 500 mV output at 25°C. Operation extends
to 150°C with reduced accuracy for all devices when operating
from a 5 V supply.
The TMP35/TMP36/TMP37 are available in low cost 3-lead
TO-92, 8-lead SOIC_N, and 5-lead SOT-23 surface-mount
packages.
Document Feedback
Rev. H
Information furnished by Analog Devices is believed to be accurate and reliable. However, no
responsi bility is assumed by Analog Devices for its use, nor for any infringements of patents or other
rights of third parties that may result from its use. Specifications subject to change without notice. No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
Trademarks and registered trademarks are the property of their respective owners.
Edits to Specifications ....................................................................... 2
Addition of New Figure 1 ................................................................. 2
Deletion of Wafer Test Limits Section ............................................ 3
6/97—Rev. 0 to Rev. A
3/96—Revision 0: Initial Version
Rev. H | Page 2 of 19
Page 3
Data Sheet TMP35/TMP36/TMP37
Parameter1
Symbol
Test Conditions/Comments
Min
Typ
Max
Unit
Scale Factor, TMP36
−40°C ≤ TA ≤ +125°C
10 mV/°C
Output Voltage Range
100 2000
mV
SPECIFICATIONS
VS = 2.7 V to 5.5 V, −40°C ≤ TA ≤ +125°C, unless otherwise noted.
Table 1.
ACCURACY
TMP35/TMP36/TMP37 (F Grade) TA = 25°C±1 ±2 °C
TMP35/TMP36/TMP37 (G Grade) TA = 25°C±1 ±3 °C
TMP35/TMP36/TMP37 (F Grade) Over rated temperature ±2 ±3 °C
TMP35/TMP36/TMP37 (G Grade) Over rated temperature ±2 ±4 °C
Scale Factor, TMP3510°C ≤ TA ≤ 125°C10 mV/°C
Scale Factor, TMP375°C ≤ TA ≤ 85°C20 mV/°C
5°C ≤ TA ≤ 100°C20 mV/°C
3.0 V ≤ VS ≤ 5.5 V
Load Regulation 0 µA ≤ IL ≤ 50 µA
−40°C ≤ TA ≤ +105°C6 20 m°C/µA
−105°C ≤ TA ≤ +125°C25 60 m°C/µA
Power Supply Rejection Ratio PSRR TA = 25°C30 100 m°C/V
3.0 V ≤ VS ≤ 5.5 V50 m°C/V
Linearity 0.5 °C
Long-Term Stability TA = 150°C for 1000 hours0.4 °C
SHUTDOWN
Logic High Input Voltage VIH VS = 2.7 V1.8 V
Logic Low Input Voltage VIL VS = 5.5 V400 mV
OUTPUT
TMP35 Output Voltage TA = 25°C250 mV
TMP36 Output Voltage TA = 25°C750 mV
TMP37 Output Voltage TA = 25°C500 mV
Output Load Current IL 0 50µA
Short-Circuit Current ISC Note 2250µA
Capacitive Load Driving CL
Device Turn-On Time
POWER SUPPLY
Supply Range VS 2.75.5V
Supply Current ISY (ON)Unloaded 50 µA
Supply Current (Shutdown) ISY (OFF)Unloaded 0.01 0.5 µA
1
Does not consider errors caused by self-heating.
2
Guaranteed but not tested.
No oscillations
Output within ±1°C, 100 kΩ||100 pF load
2
1000 10000 pF
2
0.51 ms
Rev. H | Page 3 of 19
Page 4
TMP35/TMP36/TMP37 Data Sheet
Shutdown Pin
GND ≤
≤ +VS
Peak Temperature
220°C (0°C/5°C)
IR Reflow Soldering—Pb-Free Package
ABSOLUTE MAXIMUM RATINGS
Table 2.
Parameter
Supply Voltage 7 V
Output Pin GND ≤ V
Operating Temperature Range −55°C to +150°C
Die Junction Temperature 175°C
Storage Temperature Range −65°C to +160°C
IR Reflow Soldering
Time at Peak Temperature Range 10 sec to 20 sec
Ramp-Up Rate 3°C/sec
Ramp-Down Rate −6°C/sec
Time 25°C to Peak Temperature 6 min
Peak Temperature 260°C (0°C)
Time at Peak Temperature Range 20 sec to 40 sec
Ramp-Up Rate 3°C/sec
Ramp-Down Rate −6°C/sec
Time 25°C to Peak Temperature 8 min
1
Digital inputs are protected; however, permanent damage can occur on
unprotected units from high energy electrostatic fields. Keep units in
conductive foam or packaging at all times until ready to use. Use proper
antistatic handling procedures.
2
Remove power before inserting or removing units from their sockets.
1, 2
Rating
SHUTDOWN
≤ +VS
OUT
Stresses at or above those listed under Absolute Maximum
Ratings may cause permanent damage to the product. This is a
stress rating only; functional operation of the product at these
or any other conditions above those indicated in the operational
section of this specification is not implied. Operation beyond
the maximum operating conditions for extended periods may
affect product reliability.
THERMAL RESISTANCE
θJA is specified for the worst-case conditions, that is, a device in
socket.
a. MAXIMUM LIMIT (G GRADE)
b. TYPICAL ACCURACY ERROR
c. MINIMUM LIMIT (G GRADE)
TEMPERATURE (°C)
2
–5
1
0
–1
–2
–3
–4
3
4
5
020406080100120140
a
b
c
ACCURACY ERROR (°C)
00337-008
TEMPERATURE (°C)
0.4
0.3
0
–50125
–25
0
25
50
75
100
0.2
0.1
POWER SUPPLY REJECTION (°C/V)
+V
S
= 3V TO 5.5V, NO LOAD
00337-009
FREQUENCY (Hz)
100.000
0.010
20
100k100
1k
10k
31.600
10.000
3.160
1.000
0.320
0.100
0.032
POWER SUPPLY REJECTION (
°
C/V)
00337-010
TEMPERATURE (
°C)
4
3
0
2
1
5
–50125
–250255075
100
MINIMUM SUPPLY VOLTAGE (V)
b
a
MINIMUM SUPPLY VOLTAGE REQUIRED TO MEET
DATA SHEET SPECIFICATION
NO LOAD
a. TMP35/TMP36
b. TMP37
00337-011
TYPICAL PERFORMANCE CHARACTERISTICS
Figure 5. Load Regulation vs. Temperature (m°C/µA)
Figure 6. Output Voltage vs. Temperature
Figure 8. Power Supply Rejection vs. Temperature
Figure 9. Power Supply Rejection vs. Frequency
Figure 7. Accuracy Error vs. Temperatu re
Figure 10. Minimum Supply Voltage vs. Temperature
Rev. H | Page 5 of 19
Page 6
TMP35/TMP36/TMP37 Data Sheet
SUPPLY CURRENT ( µA)
TEMPERATURE (°C)
50
40
10
30
20
60
–50125–250255075100
NO LOAD
b
a
a. +VS = 5V
b. +V
S
= 3V
00337-012
SUPPLY VOLTAGE (V)
40
30
0
20
10
50
0712345
6
SUPPLY CURRENT (µA)
TA = 25°C, NO LOAD
8
00337-013
TEMPERATURE (°C)
40
30
0
20
10
50
–50125–25
0
255075
100
a. +VS= 5V
b. +VS= 3V
NO LOAD
a
b
SUPPLY CURRENT ( nA)
00337-014
TEMPERATURE (°C)
400
300
0
200
100
–50
125–250255075
100
= +V
S
AND SHUTDOWN PINS
LOW TO HIGH (0V TO 3V)
V
OUT
SETTLES WITHIN ±1°C
= +VS AND SHUTDOWN PINS
HIGH TO LOW (3V TO 0V)
RESPONSE TIME (µs)
00337-015
TEMPERATURE (°C)
400
300
0
200
100
–50125–25
0255075
100
= SHUTDOWN P IN
HIGH TO LOW (3V TO 0V)
= SHUTDOWN P IN
LOW TO HIGH (0V TO 3V)
V
OUT
SETTLES WITHIN ±1°C
RESPONSE TIME (µs)
00337-016
TIME (µs)
0
1.0
0.8
0.6
0.4
0.2
–50250010050150 200300 350 400 450
OUTPUT VOLTAGE (V)
0
1.0
0.8
0.6
0.4
0.2
TA = 25°C
+V
S
= 3V
SHUTDOWN =
SIGNAL
TA = 25°C
+V
S
AND SHUTDOWN =
SIGNAL
00337-017
Figure 11. Supply Current vs. Temperature
Figure 12. Supply Current vs. Supply Voltage
Figure 14. V
Figure 15. V
Response Time for +VS Power-Up/Power-Down vs.
OUT
Temperature
Response Time for
OUT
SHUTDOWN
Pin vs. Temperature
Figure 13. Supply Current vs. Temperature (Shutdown = 0 V)
Figure 16. V
Response Time to
OUT
SHUTDOWN
Pin and +VS Pin vs. Time
Rev. H | Page 6 of 19
Page 7
Data Sheet TMP35/TMP36/TMP37
TIME (s)
70
0
60
50
40
30
20
10
80
90
100
110
0
100
200300400
500600
a
b
c
+VS = 3V, 5V
CHANGE (%)
a. TMP35 SO IC SOLDERE D TO 0.5" × 0.3" Cu PCB
b. TMP 36 SOIC SOL DE RE D TO 0.6" × 0.4" Cu PCB
c. TMP35 TO-92 IN SOCKE T SOLDERED TO
1" × 0.4" Cu PCB
00337-034
AIR VELOCITY (FPM)
0
60
40
20
80
140
100
120
0100200300400500600
TIME CONS TANT (s)
a
b
c
a. TMP35 SO IC SOLDERE D TO 0.5" × 0.3" Cu PCB
b. TMP 36 S O IC SOLDERE D TO 0.6" × 0.4" Cu PCB
c. TMP35 T O-92 IN SOCKET SOLDERED TO
1" × 0.4" Cu PCB
+V
S
= 3V, 5V
700
00337-018
TIME (s)
70
0
60
50
40
30
20
10
80
90
100
110
0
10
2030405060
a
b
c
CHANGE (%)
+VS = 3V, 5V
a. TMP35 SO IC SOLDERE D TO 0.5" × 0.3" Cu PCB
b. TMP 36 SOIC SOL DE RE D TO 0.6" × 0.4" Cu PCB
c. TMP35 TO-92 IN SOCKE T SOLDERED TO
1" × 0.4" Cu PCB
00337-035
10
0%
100
90
1ms
10mV
TIME/DIVISION
VOLT/DIVISION
00337-019
a
b
FREQUENCY (Hz)
2400
1000
0
1010k100
1k
2200
2000
1600
1800
1400
1200
800
600
400
200
a. TMP35/TMP36
b. TMP37
VOLTAGE NOISE DENSITY (nV/ Hz)
00337-020
Figure 17. Thermal Response Time in Still Air
Figure 18. Thermal Response Time Constant in Forced Air
Figure 20. Temperature Sensor Wideband Output Noise Voltage;
Gain = 100, BW = 157 kHz
Figure 21. Voltage Noise Spectral Density vs. Frequency
Figure 19. Thermal Response Time in Stirred Oil Bath
Rev. H | Page 7 of 19
Page 8
TMP35/TMP36/TMP37 Data Sheet
×=∆
E,Q2
E,Q1
T
BE
A
A
VVln
SHUTDOWN
V
OUT
+V
S
3X
25µA
2X
Q2
1X
R1
R2
R3
7.5µA
Q3
2X
GND
Q4
Q1
10X
6X
00337-006
FUNCTIONAL DESCRIPTION
An equivalent circuit for the TMP35/TMP36/TMP37 micropower,
centigrade temperature sensors is shown in Figure 22. The core
of the temperature sensor is a band gap core that comprises
transistors Q1 and Q2, biased by Q3 to approximately 8 µA. The
band gap core operates both Q1 and Q2 at the same collector
current level; however, because the emitter area of Q1 is 10
times that of Q2, the V
by the following relationship:
Resistors R1 and R2 are used to scale this result to produce
the output voltage transfer characteristic of each temperature
sensor and, simultaneously, R2 and R3 are used to scale the V
Q1 as an offset term in V
in the output characteristics of the three temperature sensors.
The output voltage of the temperature sensor is available at the
emitter of Q4, which buffers the band gap core and provides
load current drive. The current gain of Q4, working with the
available base current drive from the previous stage, sets the
short-circuit current limit of these devices to 250 µA.
of Q1 and the VBE of Q2 are not equal
BE
. Tab le 4 summarizes the differences
OUT
of
BE
Figure 22. Temperature Sensor Simplifi ed Equivalent Circuit
Table 4. TMP35/TMP36/TMP37 Output Characteristics
Sensor
Offset
Voltage (V)
Output Voltage
Scaling (mV/°C)
Output Voltage
at 25°C (mV)
TMP35 0 10 250
TMP36 0.510 750
TMP37 0 20 500
Rev. H | Page 8 of 19
Page 9
Data Sheet TMP35/TMP36/TMP37
T
J
θ
JC
T
C
θ
CA
C
CH
C
C
P
D
T
A
00337-021
APPLICATIONS INFORMATION
SHUTDOWN OPERATION
All TMP35/TMP36/TMP37 devices include a shutdown
capability, which reduces the power supply drain to less than
0.5 µA maximum. This feature, available only in the SOIC_N
and the SOT-23 packages, is TTL/CMOS level-compatible,
provided that the temperature sensor supply voltage is equal in
magnitude to the logic supply voltage. Internal to the TMP35/
TMP36/TMP37 at the
source to +V
is connected. This allows the
S
SHUTDOWN
pin, a pull-up current
SHUTDOWN
pin to
be driven from an open-collector/drain driver. A logic low, or
zero-volt condition, on the
SHUTDOWN
pin is required to
turn off the output stage. During shutdown, the output of the
temperature sensors becomes high impedance where the
potential of the output pin is then determined by external
circuitry. If the shutdown feature is not used, it is recommended
that the
SHUTDOWN
pin be connected to +VS (Pin 8 on the
SOIC_N; Pin 2 on the SOT-23).
The shutdown response time of these temperature sensors is
shown in Figure 14, Figure 15, and Figure 16.
MOUNTING CONSIDERATIONS
If the TMP35/TMP36/TMP37 temperature sensors are thermally
attached and protected, they can be used in any temperature
measurement application where the maximum temperature
range of the medium is between −40°C and +125°C. Properly
cemented or glued to the surface of the medium, these sensors
are within 0.01°C of the surface temperature. Caution should be
exercised, especially with T-3 packages, because the leads and
any wiring to the device can act as heat pipes, introducing
errors if the surrounding air-surface interface is not isothermal.
Avoiding this condition is easily achieved by dabbing the leads
of the temper-ature sensor and the hookup wires with a bead of
thermally conductive epoxy. This ensures that the TMP35/TMP36/
TMP37 die temperature is not affected by the surrounding air
temperature. Because plastic IC packaging technology is used,
excessive mechanical stress should be avoided when fastening the
device with a clamp or a screw-on heat tab. Thermally conductive
epoxy or glue, which must be electrically nonconductive, is
recommended under typical mounting conditions.
These temperature sensors, as well as any associated circuitry,
should be kept insulated and dry to avoid leakage and corrosion.
In wet or corrosive environments, any electrically isolated metal
or ceramic well can be used to shield the temperature sensors.
Condensation at very cold temperatures can cause errors and
should be avoided by sealing the device, using electrically nonconductive epoxy paints or dip or any one of the many printed
circuit board coatings and varnishes.
THERMAL ENVIRONMENT EFFECTS
The thermal environment in which the TMP35/TMP36/TMP37
sensors are used determines two important characteristics: selfheating effects and thermal response time. Figure 23 illustrates a
thermal model of the TMP35/TMP36/TMP37 temperature
sensors, which is useful in under-standing these characteristics.
Figure 23. Thermal Circuit Model
In the T-3 package, the thermal resistance junction-to-case, θJC,
is 120°C/W. The thermal resistance case-to-ambient, C
difference between θ
and θJC, and is determined by the char-
JA
acteristics of the thermal connection. The power dissipation of
the temperature sensor, P
, is the product of the total voltage
D
across the device and its total supply current, including any
current delivered to the load. The rise in die temperature above
the ambient temperature of the medium is given by
T
= PD × (θJC + θCA) + TA
J
Thus, the die temperature rise of a TMP35 SOT-23 package
mounted into a socket in still air at 25°C and driven from a 5 V
supply is less than 0.04°C.
The transient response of the TMP35/TMP36/TMP37 sensors
to a step change in the temperature is determined by the
thermal resistances and the thermal capacities of the die, C
and the case, C
. The thermal capacity of CC varies with the
C
measurement medium because it includes anything in direct
contact with the package. In all practical cases, the thermal
capacity of C
is the limiting factor in the thermal response time
C
of the sensor and can be represented by a single-pole RC time
constant response. Figure 17 and Figure 19 show the thermal
response time of the TMP35/TMP36/TMP37 sensors under
various conditions. The thermal time constant of a temperature
sensor is defined as the time required for the sensor to reach
63.2% of the final value for a step change in the temperature.
For example, the thermal time constant of a TMP35 SOIC
package sensor mounted onto a 0.5" × 0.3" PCB is less than
50 sec in air, whereas in a stirred oil bath, the time constant is
less than 3 sec.
, is the
A
,
CH
Rev. H | Page 9 of 19
Page 10
TMP35/TMP36/TMP37 Data Sheet
2.7V < +V
S
< 5.5V
V
OUT
0.1µF
+V
S
GND
PACKAGE
+V
S
GND
V
OUT
SOIC_N8
41
5
SOT-23
251
4
TO-921
32NA
PIN ASSIGNMENTS
SHUTDOWN
TMP3x
00337-022
SHUTDOWN
()
()
AD589
R4R3
R3
TMP35
R2R1
R1
V
OUT
+
+
+
=
SENSOR
TCV
OUT
R1 (kΩ)
TMP35
1mV/°F45.31010
374
TMP372mV/°F45.310
10182
R2 (kΩ) R3 (kΩ)
R4 (kΩ)
TMP35/
TMP37
GND
R1
R2
R3
R4
AD589
1.23V
0.1µF
V
OUT
+V
S
V
OUT
+V
S
–
+
00337-023
BASIC TEMPERATURE SENSOR CONNECTIONS
Figure 24 illustrates the basic circuit configuration for the
TMP35/TMP36/TMP37 temperature sensors. The table in
Figure 24 shows the pin assignments of the temperature sensors
for the three package types. For the SOT-23, Pin 3 is labeled NC,
as are Pin 2, Pin 3, Pin 6, and Pin 7 on the SOIC_N package. It
is recommended that no electrical connections be made to these
pins. If the shutdown feature is not needed on the SOT-23 or on
the SOIC_N package, the
connected to +V
.
S
SHUTDOWN
pin should be
FAHRENHEIT THERMOMETERS
Although the TMP35/TMP36/TMP37 temperature sensors are
centigrade temperature sensors, a few components can be used
to convert the output voltage and transfer characteristics to
directly read Fahrenheit temperatures. Figure 25 shows an
example of a simple Fahrenheit thermometer using either the
TMP35 or the TMP37. Using the TMP35, this circuit can be
used to sense temperatures from 41°F to 257°F with an output
transfer characteristic of 1 mV/°F; using the TMP37, this circuit
can be used to sense temperatures from 41°F to 212°F with an
output transfer characteristic of 2 mV/°F. This particular
approach does not lend itself to the TMP36 because of its
inherent 0.5 V output offset. The circuit is constructed with an
AD589, a 1.23 V voltage reference, and four resistors whose
values for each sensor are shown in the table in Figure 25. The
scaling of the output resistance levels ensures minimum output
loading on the temp-erature sensors. A generalized expression
for the transfer equation of the circuit is given by
Figure 24. Basic Temperature Sensor Circuit Configuration
Note the 0.1 µF bypass capacitor on the input. This capacitor
should be a ceramic type, have very short leads (surface-mount
is preferable), and be located as close as possible in physical
proximity to the temperature sensor supply pin. Because these
temperature sensors operate on very little supply current and
may be exposed to very hostile electrical environments, it is
important to minimize the effects of radio frequency interference
(RFI) on these devices. The effect of RFI on these temperature
sensors specifically and on analog ICs in general is manifested as
abnormal dc shifts in the output voltage due to the rectification
of the high frequency ambient noise by the IC. When the
devices are operated in the presence of high frequency radiated
or conducted noise, a large value tantalum capacitor (±2.2 µF)
placed across the 0.1 µF ceramic capacitor may offer additional
noise immunity.
where:
TMP35 is the output voltage of the TMP35 or the TMP37 at the
measurement temperature, T
.
M
AD589 is the output voltage of the reference, that is, 1.23 V.
The output voltage of this circuit is not referenced to the
circ u it’s common ground. If this output voltage were applied
directly to the input of an ADC, the ADC common ground
should be adjusted accordingly.
Rev. H | Page 10 of 19
Figure 25. TMP35/TMP37 Fahrenheit Thermometers
Page 11
Data Sheet TMP35/TMP36/TMP37
TMP36
GND
0.1µF
V
OUT
+V
S
R1
45.3kΩ
R2
10kΩ
+V
S
V
OUT
@ –40°F = 18mV
V
OUT
@ +257°F = 315mV
00337-024
V
OUT
@ 1mV/°F – 58°F
()
−
+
+
=
2
1
S
OUT
V
R3
R4
TMP36
R3
R4
R6R5
R6
V
ELEMENT
R3
R4
R5
R6
VALUE
V
OUT
R1
50kΩ
+V
S
ADM660
TMP36
OP193
R2
50kΩ
R3
R4
+3V
C1
10µF
R5
0.1µF
10µF
–3V
10µF/0.1µF
GND
NC
10µF
NC
R6
1
2
3
4
5
6
7
2
3
4
6
7
8
258.6kΩ
10kΩ
47.7kΩ
10kΩ
+
+
+
+
–
+
V
OUT
@ 1mV/°F
–40°F ≤ T
A
≤ +257°F
00337-025
The same circuit principles can be applied to the TMP36, but
because of the inherent offset of the TMP36, the circuit uses only
two resistors, as shown in Figure 26. In this circuit, the output
voltage transfer characteristic is 1 mV/°F but is referenced to
the common ground of the circuit; however, there is a 58 mV
(58°F) offset in the output voltage. For example, the output
voltage of the circuit reads 18 mV if the TMP36 is placed in a
−40°F ambient environment and 315 mV at +257°F.
At the expense of additional circuitry, the offset produced by
the circuit in Figure 26 can be avoided by using the circuit in
Figure 27. In this circuit, the output of the TMP36 is conditioned
by a single-supply, micropower op amp, the OP193. Although
the entire circuit operates from a single 3 V supply, the output
voltage of the circuit reads the temperature directly, with a
transfer characteristic of 1 mV/°F, without offset. This is accomplished through an ADM660, which is a supply voltage inverter.
The 3 V supply is inverted and applied to the V− terminal of the
OP193. Thus, for a temperature range between −40°F and +257°F,
the output of the circuit reads −40 mV to +257 mV. A general
expression for the transfer equation of the circuit is given by
Figure 26. TMP36 Fahrenheit Thermometer Version 1
Figure 27. TMP36 Fahrenheit Thermometer Version 2
Rev. H | Page 11 of 19
Page 12
TMP35/TMP36/TMP37 Data Sheet
OP193
0.1µF
2
3
4
6
7
V
TEMP(AVG)
@ 10mV/°C FO R TMP35/TM P 36
@ 20mV/°C FO R TMP37
2.7V < +V
S
< 5.5V
FOR R1 = R2 = R3 = R;
V
TEMP(AVG)
= 1 (TMP3x1 + TMP3x2 + TMP3x3)
3
R1
300kΩ
R2
300kΩ
R3
300kΩ
R4
7.5kΩ
R1
3
R4 = R6
R6
7.5kΩ
R5
100kΩ
R5 =
TMP3x
TMP3x
TMP3x
–
+
00337-026
TMP36
@ T1
0.1µF
0.1µF
2
3
4
6
7
OP193
1µF
V
OUT
R3
1
R4
1
R2
1
R1
1
2.7V < +VS < 5.5V
TMP36
@ T2
R5
100kΩ
R6
100kΩ
V
OUT
= T2 – T1 @ 10mV/°C
V
S
2
NOTE:
1
R1–R4, CADDOCK T914–100k–100, OR EQUIVALENT.
0.1µF
R7
100kΩ
R8
25kΩ
R9
25kΩ
0°C ≤ T
A
≤ 125°C
CENTERED AT
CENTERED AT
–
+
00337-027
AVERAGE AND DIFFERENTIAL TEMPERATURE
MEASUREMENT
In many commercial and industrial environments, temperature
sensors often measure the average temperature in a building, or
the difference in temperature between two locations on a factory
floor or in an industrial process. The circuits in Figure 28 and
Figure 29 demonstrate an inexpensive approach to average and
differential temperature measurement.
In Figure 28, an OP193 sums the outputs of three temperature
sensors to produce an output voltage scaled by 10 mV/°C that
represents the average temperature at three locations. The circuit
can be extended to include as many temperature sensors as
required as long as the transfer equation of the circuit is
maintained. In this application, it is recommended that one
temperature sensor type be used throughout the circuit;
otherwise, the output voltage of the circuit cannot produce an
accurate reading of the various ambient conditions.
The circuit in Figure 29 illustrates how a pair of TMP35/TMP36/
TMP37 sensors used with an OP193 configured as a difference
amplifier can read the difference in temperature between two
locations. In these applications, it is always possible that one
temperature sensor is reading a temperature below that of the
other sensor. To accommodate this condition, the output of the
OP193 is offset to a voltage at one-half the supply via R5 and
R6. Thus, the output voltage of the circuit is measured relative
to this point, as shown in Figure 29. Using the TMP36, the
output voltage of the circuit is scaled by 10 mV/°C. To minimize
the error in the difference between the two measured
temperatures, a common, readily available thin-film resistor
network is used for R1 to R4.
Figure 28. Configuring Multiple Sensors for
Average Temperature Measurements
Rev. H | Page 12 of 19
Figure 29. Configuring Multiple Sensors for
Differential Temperature Measurements
Page 13
Data Sheet TMP35/TMP36/TMP37
()
CMP402SWINGLOGICHYS
V
R2
R1
V
,
=
R2
1MΩ
3
4
V
OUT
+V
S
TMP35
0.1µF
GND
0.1µF
CMP402
INTERRUPT
<80°C
>80°C
REF191
R1A
10kΩ
R1B
10kΩ
3.3V
2
6
C
L
1000pF
R3
16kΩ
1µF
R4
10kΩ
V
REF
0.1µF
0.1µF
C1 = CMP402
4
1
2
4
3
14
13
5
6
R5
100kΩ
+
–
+
00337-028
MICROPROCESSOR INTERRUPT GENERATOR
These inexpensive temperature sensors can be used with a
voltage reference and an analog comparator to configure an
interrupt generator for microprocessor applications. With the
popularity of fast microprocessors, the need to indicate a
microprocessor overtemperature condition has grown
tremendously. The circuit in Figure 30 demonstrates one way to
generate an interrupt using a TMP35, a CMP402 analog
comparator, and a REF191, a 2 V precision voltage reference.
The circuit is designed to produce a logic high interrupt signal
if the microprocessor temperature exceeds 80°C. This 80°C trip
point was arbitrarily chosen (final value set by the microprocessor
thermal reference design) and is set using an R3 to R4 voltage
divider of the REF191 output voltage. Because the output of the
TMP35 is scaled by 10 mV/°C, the voltage at the inverting
terminal of the CMP402 is set to 0.8 V.
Because temperature is a slowly moving quantity, the possibility
for comparator chatter exists. To avoid this condition, hysteresis
is used around the comparator. In this application, a hysteresis
of 5°C about the trip point was arbitrarily chosen; the ultimate
value for hysteresis should be determined by the end application.
The output logic voltage swing of the comparator with R1 and
R2 determines the amount of comparator hysteresis. Using a
3.3 V supply, the output logic voltage swing of the CMP402 is
2.6 V; therefore, for a hysteresis of 5°C (50 mV at 10 mV/°C),
R1 is set to 20 kΩ, and R2 is set to 1 MΩ. An expression for the
hysteresis of this circuit is given by
Because this circuit is probably used in close proximity to high
speed digital circuits, R1 is split into equal values and a 1000 pF
capacitor is used to form a low-pass filter on the output of the
TMP35. Furthermore, to prevent high frequency noise from
contaminating the comparator trip point, a 0.1 µF capacitor is
used across R4.
THERMOCOUPLE SIGNAL CONDITIONING WITH
COLD-JUNCTION COMPENSATION
The circuit in Figure 31 conditions the output of a Type K
thermocouple, while providing cold-junction compensation for
temperatures between 0°C and 250°C. The circuit operates from
a single 3.3 V to 5.5 V supply and is designed to produce an
output voltage transfer characteristic of 10 mV/°C.
A Type K thermocouple exhibits a Seebeck coefficient of
approximately 41 µV/°C; therefore, at the cold junction, the
TMP35, with a temperature coefficient of 10 mV/°C, is used
with R1 and R2 to introduce an opposing cold-junction temperature coefficient of −41 µV/°C. This prevents the isothermal,
cold-junction connection between the PCB tracks of the circuit
and the wires of the thermocouple from introducing an error in
the measured temperature. This compensation works extremely
well for circuit ambient temperatures in the range of 20°C to 50°C.
Over a 250°C measurement temperature range, the thermocouple
produces an output voltage change of 10.151 m V. Because the
required output full-scale voltage of the circuit is 2.5 V, the gain
of the circuit is set to 246.3. Choosing R4 equal to 4.99 kΩ sets
R5 equal to 1.22 MΩ. Because the closest 1% value for R5 is
1.21 MΩ, a 50 kΩ potentiometer is used with R5 for fine trim of
the full-scale output voltage. Although the OP193 is a superior
single-supply, micropower operational amplifier, its output stage
is not rail-to-rail; therefore, the 0°C output voltage level is 0.1 V.
If this circuit is digitized by a single-supply ADC, the ADC
common should be adjusted to 0.1 V accordingly.
Figure 31. Single-Supply, Type K Thermocouple Signal Conditioning Circuit with Cold-Junction Compensation
Rev. H | Page 14 of 19
Page 15
Data Sheet TMP35/TMP36/TMP37
TWISTED PAIR
BELDEN TYPE 9502
OR EQUIVALENT
TMP3x
R2
R1
4.7kΩ
V
OUT
0.1µF
2N2907
0.01µF
GND
+V
S
5V
R3
V
OUT
SENSOR
R2 R3
TMP35634
634
TMP36887
887
TMP371k1k
00337-030
×
+
×
×
=
R2
R3V
R1
R3TMP3x
R7
1
I
REF
OUT
USING TMP35/TMP36/TMP37 SENSORS IN
REMOTE LOCATIONS
In many industrial environments, sensors are required to
operate in the presence of high ambient noise. These noise
sources take many forms, for example, SCR transients, relays,
radio transmitters, arc welders, and ac motors. They can also
be used at considerable distances from the signal conditioning
circuitry. These high noise environments are typically in the
form of electric fields, so the voltage output of the temperature
sensor can be susceptible to contamination from these noise
sources.
Figure 32 illustrates a way to convert the output voltage of a
TMP35/TMP36/TMP37 sensor into a current to be transmitted
down a long twisted pair shielded cable to a ground referenced
receiver. The temperature sensors are not capable of high output
current operation; thus, a standard PNP transistor is used to
boost the output current drive of the circuit. As shown in the
table in Figure 32, the values of R2 and R3 were chosen to
produce an arbitrary full-scale output current of 2 mA. Lower
values for the full-scale current are not recommended. The
minimum-scale output current produced by the circuit could be
contaminated by ambient magnetic fields operating in the near
vicinity of the circuit/cable pair. Because the circuit uses an
external transistor, the minimum recommended operating
voltage for this circuit is 5 V. To minimize the effects of EMI (or
RFI), both the circuit and the temperature sensor supply pins
are bypassed with good quality ceramic capacitors.
TEMPERATURE TO 4–20 mA LOOP TRANSMITTER
In many process control applications, 2-wire transmitters are
used to convey analog signals through noisy ambient environments. These current transmitters use a zero-scale signal current
of 4 mA, which can be used to power the signal conditioning
circuitry of the transmitter. The full-scale output signal in these
transmitters is 20 mA.
Figure 33 illustrates a circuit that transmits temperature information in this fashion. Using a TMP35/TMP36/TMP37 as the
temperature sensor, the output current is linearly proportional
to the temperature of the medium. The entire circuit operates
from the 3 V output of the REF193. The REF193 requires no
external trimming because of its tight initial output voltage
tolerance and the low supply current of the TMP35/TMP36/
TMP37, the OP193, and the REF193. The entire circuit consumes
less than 3 mA from a total budget of 4 mA. The OP193 regulates
the output current to satisfy the current summation at the
noninverting node of the OP193. A generalized expression for
the KCL equation at Pin 3 of the OP193 is given by
For each temperature sensor, Tabl e 5 provides the values for the
components P1, P2, and R1 to R4.
Table 5. Circuit Element Values for Loop Transmitter
Figure 32. Remote, 2-Wire Boosted Output Current Temperature Sensor
The 4 mA offset trim is provided by P2, and P1 provides the
full-scale gain trim of the circuit at 20 mA. These two trims do
not interact because the noninverting input of the OP193 is
held at a virtual ground. The zero-scale and full-scale output
currents of the circuit are adjusted according to the operating
temperature range of each temperature sensor. The Schottky
diode, D1, is required in this circuit to prevent loop supply
power-on transients from pulling the noninverting input of the
OP193 more than 300 mV below its inverting input. Without
this diode, such transients can cause phase reversal of the
operational amplifier and possible latch-up of the transmitter.
The loop supply voltage compliance of the circuit is limited by
the maximum applied input voltage to the REF193; it is from
9 V to 18 V.
Rev. H | Page 15 of 19
Page 16
TMP35/TMP36/TMP37 Data Sheet
V
3V
6
REF193
2
1
R2
1
P2
P1
20mA
R3
4mA
ADJUST
2
1
1
3
D1
R4
D1: HP5082-2810
+V
S
GND
R1
V
OUT
TMP3x
NOTE:
1
SEE TEXT FOR VALUES.
1
ADJUST
Figure 33. Temperature to 4–20 mA Loop Transmitter
TEMPERATURE-TO-FREQUENCY CONVERTER
Another common method of transmitting analog information
from a remote location is to convert a voltage to an equivalent
value in the frequency domain. This is readily done with any of
the low cost, monolithic voltage-to-frequency converters (VFCs)
available. These VFCs feature a robust, open-collector output
transistor for easy interfacing to digital circuitry. The digital
signal produced by the VFC is less susceptible to contamination
from external noise sources and line voltage drops because the
only important information is the frequency of the digital signal. When the conversions between temperature and frequency
are done accurately, the temperature data from the sensors can
be reliably transmitted.
The circuit in Figure 34 illustrates a method by which the
outputs of these temperature sensors can be converted to a
frequency using the AD654. The output signal of the AD654 is
a square wave that is proportional to the dc input voltage across
Pin 4 and Pin 3. The transfer equation of the circuit is given by
f
OUT
VV
OFFSETTPM
CR
)(10
TT
–
OP193
+
1
+
7
4
1µF
0.1µF
6
10µF/0.1µF
4
R5
100kΩ
R6
100kΩ
100Ω
R7
Q1
2N1711
I
L
TMP3x
P2
100kΩ
5
+V
S
V
GND
1
R
T
5V
R
OFF1
470Ω
SENSOR R
TMP35
TMP36
TMP37
V
LOOP
9V TO 18V
V
OUT
R
L
250Ω
0.1µF
4
OUT
3
R1
P1
f
OUT
OFFSET
R
OFF2
10Ω
(R1 + P1)C
T
11.8kΩ + 500Ω
16.2kΩ + 500Ω
18.2kΩ + 1kΩ
00337-032
1
C
T
6
8
7
AD654
5
2
NB: ATTA (MIN),
NOTE:
1
RT AND CT – SEE TABLE
T
1.7nF
1.8nF
2.1nF
R
PU
5kΩ
1
f
OUT
f
= 0Hz
OUT
0337-031
Figure 34. Temperature-to-Frequency Converter
Rev. H | Page 16 of 19
Page 17
Data Sheet TMP35/TMP36/TMP37
TMP3x
0.1µF
GND
+V
S
750Ω
LONG CABLE OR
HEAVY CAPACITIVE
LOADS
V
OUT
00337-033
An offset trim network (f
circuit to set f
to 0 Hz when the minimum output voltage of
OUT
the temperature sensor is reached. Potentiometer P1 is required
to calibrate the absolute accuracy of the AD654. The table in
Figure 34 illustrates the circuit element values for each of the
three sensors. The nominal offset voltage required for 0 Hz
output from the TMP35 is 50 mV; for the TMP36 and TMP37,
the offset voltage required is 100 mV. For the circuit values
shown, the output frequency transfer characteristic of the
circuit was set at 50 Hz/°C in all cases. At the receiving end, a
frequency-to-voltage converter (FVC) can be used to convert
the frequency back to a dc voltage for further processing. One
such FVC is the AD650.
For complete information about the AD650 and the AD654,
consult the individual data sheets for those devices.
DRIVING LONG CABLES OR HEAVY CAPACITIVE
LOADS
Although the TMP35/TMP36/TMP37 temperature sensors
can drive capacitive loads up to 10,000 pF without oscillation,
output voltage transient response times can be improved by
using a small resistor in series with the output of the temperature
sensor, as shown in Figure 35. As an added benefit, this resistor
forms a low-pass filter with the cable capacitance, which helps
to reduce bandwidth noise. Because the temperature sensor is
likely to be used in environments where the ambient noise level
can be very high, this resistor helps to prevent rectification by
the devices of the high frequency noise. The combination of this
resistor and the supply bypass capacitor offers the best protection.
OFFSET ) is included with this
OUT
COMMENTARY ON LONG-TERM STABILITY
The concept of long-term stability has been used for many years
to describe the amount of parameter shift that occurs during
the lifetime of an IC. This is a concept that has been typically
applied to both voltage references and monolithic temperature
sensors. Unfortunately, integrated circuits cannot be evaluated
at room temperature (25°C) for 10 years or more to determine
this shift. As a result, manufacturers very typically perform
accelerated lifetime testing of integrated circuits by operating
ICs at elevated temperatures (between 125°C and 150°C) over a
shorter period of time (typically, between 500 and 1000 hours).
As a result of this operation, the lifetime of an integrated circuit
is significantly accelerated due to the increase in rates of reaction
within the semiconductor material.
Figure 35. Driving Long Cables or Heavy Capacitive Loads
Rev. H | Page 17 of 19
Page 18
TMP35/TMP36/TMP37 Data Sheet
CO
N
TR
O
LL
IN
G
DI
ME
NSION
S A
RE
I
N M
IL
L
IM
E
TE
RS
;
IN
CH
D
IM
EN
S
IO
NS
(I
N PA
RE
N
TH
ES
E
S)
AR
E
RO
U
ND
ED
-
OF
F MILLIMETER EQUIVALEN
TS FOR
REFERENCE ON
LYA
ND A
RE NO
T AP
PRO
PRIATE FOR USE IN DESIGN.
CO
MP
L
IA
N
T TO JEDEC STANDARDS MS-012
-
AA
01
2407
-A
0.
25
(
0.
00
9
8)
0.
1
7 (
0
.0
06
7
)
1
.2
7
(0
.
05
00
)
0.40 (0.0157)
0.50 (0.01
96
)
0.25 (0.0
0
99
)
4
5°
8°
0
°
1.
7
5 (
0.
0
68
8)
1
.3
5
(0.0532)
SE
A
TI
N
G
P
L
AN
E
0.
2
5 (
0
.0098)
0.
10
(
0.
00
4
0)
4
1
85
5.
00
(0
.
19
68
)
4.
8
0(0.1890)
4.00 (
0
.1
57
4
)
3.80 (
0.
1
49
7)
1.
27
(
0.
05
0
0)
B
SC
6.20 (0.2441)
5.
80
(
0.
2
28
4)
0
.5
1
(0
.
02
01
)
0.31 (0.0122)
C
O
PL
AN
A
RI
TY
0.10
COMPLIANT TO JEDEC STANDARDS MO-178-AA
10°
5°
0°
SEATING
PLANE
1.90
BSC
0.95 BSC
0.60
BSC
5
123
4
3.00
2.90
2.80
3.00
2.80
2.60
1.70
1.60
1.50
1.30
1.15
0.90
0.15 MAX
0.05 MIN
1.45 MAX
0.95 MIN
0.20 MAX
0.08 MIN
0.50 MAX
0.35 MIN
0.55
0.45
0.35
11-01-2010-A
OUTLINE DIMENSIONS
Figure 36. 8-Lead Standard Small Outline Package [SOIC_N]
Narrow Body
(R-8)
Dimensions shown in millimeters and (inches)
Figure 37. 5-Lead Small Outline Transistor Package [SOT-23]
(RJ-5)
Dimensions shown in millimeters
Rev. H | Page 18 of 19
Page 19
Data Sheet TMP35/TMP36/TMP37
042208-A
CONTROLLING DIMENSIONS ARE IN INCHES; MILLIMETER DIMENSIONS
(IN PARENTHES E S ) ARE ROUNDED-OFF EQUIVAL E NTS FOR
REFERENCE ONLY AND ARE NOT AP P ROPRIATE F OR USE IN DESIGN.
TMP35FSZ-REEL ±2.0 10°C to 125°C 8-Lead Standard Small Outline Package (SOIC_N) R-8
TMP35GRTZ-REEL7 ±3.0 10°C to 125°C 5-Lead Small Outline Transistor Package (SOT-23) RJ-5 #T11
TMP35GT9Z ±3.0 10°C to 125°C 3-Pin Plastic Header-Style Package (TO-92) T-3-1
ADW75001Z-0REEL7 ±3.0 −40°C to +125°C 5-Lead Small Outline Transistor Package (SOT-23) RJ-5 #T6G
TMP36FS ±2.0 −40°C to +125°C 8-Lead Standard Small Outline Package (SOIC_N) R-8
TMP36FS-REEL ±2.0 −40°C to +125°C 8-Lead Standard Small Outline Package (SOIC_N) R-8
TMP36FSZ ±2.0 −40°C to +125°C 8-Lead Standard Small Outline Package (SOIC_N) R-8
TMP36FSZ-REEL ±2.0 −40°C to +125°C 8-Lead Standard Small Outline Package (SOIC_N) R-8
TMP36GRT-REEL7 ±3.0 −40°C to +125°C 5-Lead Small Outline Transistor Package (SOT-23) RJ-5 T6G
TMP36GSZ ±3.0 −40°C to +125°C 8-Lead Standard Small Outline Package (SOIC_N) R-8
TMP36GSZ-REEL ±3.0 −40°C to +125°C 8-Lead Standard Small Outline Package (SOIC_N) R-8
TMP36GSZ-REEL7 ±3.0 −40°C to +125°C 8-Lead Standard Small Outline Package (SOIC_N) R-8
TMP36GT9 ±3.0 −40°C to +125°C 3-Pin Plastic Header-Style Package (TO-92) T-3-1
TMP36GT9Z ±3.0 −40°C to +125°C 3-Pin Plastic Header-Style Package (TO-92) T-3-1
TMP36-PT7 −40°C to +125°C Chips or Die
TMP37FT9Z ±2.0 5°C to 100°C 3-Pin Plastic Header-Style Package (TO-92) T-3-1
TMP37GRTZ-REEL7 ±3.0 5°C to 100°C 5-Lead Small Outline Transistor Package (SOT-23) RJ-5 #T12
1
Z = RoHS Compliant Part.
2
W = Qualified for Automotive Applications.
Linear Operating
Temperature Range
Package Description
Package
Option
Branding
AUTOMOTIVE PRODUCTS
The ADW75001Z-0REEL7 model is available with controlled manufacturing to support the quality and reliability requirements of
automotive applications. Note that this automotive model may have specifications that differ from the commercial models; therefore,
designers should review the Specifications section of this data sheet carefully. Only automotive grade products shown are available for use
in automotive applications. Contact your local Analog Devices account representative for specific product ordering information and to
obtain the specific Automotive Reliability reports for these models.
registered trademarks are the property of their respective owners.
D00337-0-5/15(H)
Rev. H | Page 19 of 19
Page 20
Mouser Electronics
Authorized Distributor
Click to View Pricing, Inventory, Delivery & Lifecycle Information:
Analog Devices Inc.: TMP36FSZTMP35GT9ZTMP36GSZ-REELTMP36GT9ZTMP37FT9ZTMP36GT9TMP36GSZ-REEL7