Analog Devices TMP12 Datasheet
a
TOP VIEW
(Not to Scale)
8
V+
1
VREF
7
OVER
2
SET HIGH
6
UNDERSET LOW
3
5
HEATERGND
4
Airflow and Temperature Sensor
TMP12*
FEATURES
Temperature Sensor Includes 100 Ω Heater
Heater Provides Power IC Emulation
Accuracy 63°C typ. from 240°C to 1100°C
Operation to 1150°C
5 mV/°C Internal Scale-Factor
Resistor Programmable Temperature Setpoints
20 mA Open-Collector Setpoint Outputs
Programmable Thermal Hysteresis
Internal 2.5 V Reference
Single 5 V Operation
400 µA Quiescent Current (Heater OFF)
Minimal External Components
APPLICATIONS
System Airflow Sensor
Equipment Over-Temperature Sensor
Over-Temperature Protection
Power Supply Thermal Sensor
Low-Cost Fan Controller
GENERAL DESCRIPTION
The TMP12 is a silicon-based airflow and temperature sensor
designed to be placed in the same airstream as heat generating
components that require cooling. Fan cooling may be required
continuously, or during peak power demands, e.g. for a power
supply, and if the cooling systems fails, system reliability and/or
safety may be impaired. By monitoring temperature while emulating a power IC, the TMP12 can provide a warning of cooling
system failure.
The TMP12 generates an internal voltage that is linearly proportional to Celsius (Centigrade) temperature, nominally
15 mV/°C. The linearized output is compared with voltages
from an external resistive divider connected to the TMP12’s
2.5 V precision reference. The divider sets up one or two reference voltages, as required by the user, providing one or two
temperature setpoints. Comparator outputs are open-collector
transistors able to sink over 20 mA. There is an on-board hysteresis generator provided to speed up the temperature-setpoint
output transitions, this also reduces erratic output transitions in
noisy environments. Hysteresis is programmed by the external
resistor chain and is determined by the total current drawn from
the 2.5 V reference. The TMP12 airflow sensor also incorporates a precision, low temperature coefficient 100 Ω heater
resistor that may be connected directly to an external 5 V supply. When the heater is activated it raises the die temperature in
FUNCTIONAL BLOCK DIAGRAM
HYSTERESIS
VREF
SET
HIGH
SET
LOW
GND
CURRENT
CURRENT
MIRROR
VOLTAGE
REFERENCE
AND
SENSOR
WINDOW
COMPARATOR
1kΩ
+
-
I
HYS
+
+
-
HYSTERESIS
VOLTAGE
V+
OVER
UNDER
HEATER
100Ω
PINOUTS
DIP And SO
the DIP package approximately 20°C above ambient (in still
air). The purpose of the heater in the TMP12 is to emulate a
power IC, such as a regulator or Pentium CPU which has a high
internal dissipation.
When subjected to a fast airflow, the package and die temperatures of the power device and the TMP12 (if located in the
same airstream) will be reduced by an amount proportional to
the rate of airflow. The internal temperature rise of the TMP12
may be reduced by placing a resistor in series with the heater, or
reducing the heater voltage.
The TMP12 is intended for single 5 V supply operation, but will
operate on a 12 V supply. The heater is designed to operate from
5 V only. Specified temperature range is from 240°C to 1125°C,
operation extends to 1150°C at 5 V with reduced accuracy.
The TMP12 is available in 8-pin plastic DIP and SO packages.
*Protected by U.S. Patent No. 5,195,827.
REV. 0
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
© Analog Devices, Inc., 1995
One Technology Way, P.O. Box 9106, Norwood. MA 02062-9106, U.S.A.
Tel: 617/329-4700 Fax: 617/326-8703
TMP12–SPECIFICATIONS
(VS = 15 V, 240°C ≤ TA ≤ 1125°C unless otherwise noted.)
Parameter Symbol Conditions Min Typ Max Units
ACCURACY
Accuracy (High, Low Setpoints) T
Accuracy (High, Low Setpoints) T
Internal Scale Factor T
Power Supply Rejection Ratio PSRR 4.5 V ≤ 1V
Linearity T
Repeatability T
Long Term Stability T
= 125°C 62 63 °C
A
= 240°C to 1100°C 63 65 °C
A
= 240°C to 1100°C 14.9 15 15.1 mV/°C
A
= 240°C to 1125°C 0.5 °C
A
= 240°C to 1125°C 0.3 °C
A
= 1125°C for 1 k Hrs 0.3 °C
A
≤ 5.5 V 0.1 0.5 °C/V
S
SETPOINT INPUTS
Offset Voltage V
OS
Output Voltage Drift TCV
Input Bias Current I
B
OS
0.25 mV
3 µV/°C
25 100 nA
VREF OUTPUT
Output Voltage VREF T
Output Voltage VREF T
= 125°C, No Load 2.49 2.50 2.51 V
A
= 240°C to 1100°C, 2.5 60.015 V
A
No Load
Output Drift TC
Output Current, Zero Hysteresis I
VREF
Hysteresis Current Scale Factor SF
VREF
HYS
210 ppm/°C
7 µA
5 µA/°C
OPEN-COLLECTOR OUTPUTS
I
Output Low Voltage V
Output Low Voltage V
Output Leakage Current I
Fall Time t
OL
OL
OH
HL
= 1.6 mA 0.25 0.4 V
SINK
I
= 20 mA 0.6 V
SINK
V
= 12 V 1 100 µA
S
See Test Load 40 ns
HEATER
T
Resistance R
H
Temperature Coefficient T
Maximum Continuous Current I
H
= 125°C 97 100 103 Ω
A
= 240°C to 1125°C 100 ppm/°C
A
See Note 1 60 mA
POWER SUPPLY
Supply Range 1V
Supply Current I
NOTES
1
Guaranteed but not tested.
2
TMP12 is specified for operation from a 5 V supply. However, operation is allowed up to a 12 V supply, but not tested at 12 V. Maximum heater supply is 6 V.
S
SY
I
SY
Unloaded at 15 V 400 600 µA
Unloaded at 112 V
2
4.5 5.5 V
450 µA
Specifications subject to change without notice.
TEST LOAD
1kΩ
20pF
REV. 0–2–
TMP12
WAFER TEST LIMITS
(VS = 15 V, GND = O V, TA = 125°C, unless otherwise noted.)
Parameter Symbol Conditions Min Typ Max Units
ACCURACY
Accuracy (High, Low Setpoints) T
Internal Scale Factor T
= 125°C 63 °C
A
= 125°C 14.9 15 15.1 mV/°C
A
SETPOINT INPUTS
Input Bias Current I
B
100 nA
VREF OUTPUT
Output Voltage VREF T
= 125°C, No Load 2.49 2.51 V
A
OPEN-COLLECTOR OUTPUTS
I
Output Low Voltage V
Output Leakage Current I
OL
OH
= 1.6 mA 0.4 V
SINK
V
= 12 V 100 µA
S
HEATER
Resistance R
H
T
= 125°C 97 100 103 Ω
A
POWER SUPPLY
Supply Range 1V
Supply Current I
NOTE
Electrical tests are performed at wafer probe to the limits shown. Due to variations in assembly methods and normal yield loss, yield after packaging is not guaranteed
for standard product dice. Consult factory to negotiate specifications based on dice lot qualification through sample lot assembly and testing.
SY
S
Unloaded at 15 V 600 µA
4.5 5.5 V
DICE CHARACTERISTICS
Die Size 0.078 3 0.071 inch, 5,538 sq. mils
(1.98 3 1.80 mm, 3.57 sq. mm)
Transistor Count: 105
8
7
6
5
1. VREF
2. SET HIGH INPUT
3. SET LOW INPUT
4. GND
5. HEATER
UNDER OUTPUT
6.
OVER OUTPUT
7.
8. V1
1
2
3
4
For additional DICE ordering information, refer to databook.
CAUTION
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily
accumulate on the human body and test equipment and can discharge without detection.
Although the TMP12 features proprietary ESD protection circuitry, permanent damage may
occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD
precautions are recommended to avoid performance degradation or loss of functionality.
WARNING!
ESD SENSITIVE DEVICE
REV. 0
–3–
TMP12
ABSOLUTE MAXIMUM RATINGS*
Supply Voltage. . . . . . . . . . . . . . . . . . . . . . . . 20.3 V to 115 V
Heater Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 V
Setpoint Input Voltage . . . . . . . . . . . 20.3 V to [(V1) 10.3 V]
Reference Output Current . . . . . . . . . . . . . . . . . . . . . . . . 2 mA
Open-Collector Output Current . . . . . . . . . . . . . . . . . . 50 mA
Open-Collector Output Voltage . . . . . . . . . . . . . . . . . . . 115 V
Operating Temperature Range . . . . . . . . . . 255°C to 1150°C
Dice Junction Temperature . . . . . . . . . . . . . . . . . . . . . 1175°C
Storage Temperature Range . . . . . . . . . . . . 265°C to 1160°C
Lead Temperature(Soldering, 60 sec) . . . . . . . . . . . . . 1300°C
Package Type Θ
JA
8-Pin Plastic DIP (P) 103
8-Lead SOIC (S) 158
NOTES
1
ΘJA is specified for device in socket (worst case conditions).
2
ΘJA is specified for device mounted on PCB.
CAUTION
Θ
1
43 °C/W
2
43 °C/W
JC
Units
1. Stresses above those listed under “Absolute Maximum
Ratings” may cause permanent damage to the device. This is a
stress rating only and functional operation at or above this
specification is not implied. Exposure to the above maximum
rating conditions for extended periods may affect device reliability.
2. Digital inputs and outputs are protected, however, permanent
damage may 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.
3. Remove power before inserting or removing units from their
sockets.
ORDERING GUIDE
FUNCTIONAL DESCRIPTION
The TMP12 incorporates a heating element, temperature sensor, and two user-selectable setpoint comparators on a single
substrate. By generating a known amount of heat, and using the
setpoint comparators to monitor the resulting temperature rise,
the TMP12 can indirectly monitor the performance of a
system’s cooling fan.
The TMP12 temperature sensor section consists of a bandgap
voltage reference which provides both a constant 2.5 V output
and a voltage which is proportional to absolute temperature
(VPTAT). The VPTAT has a precise temperature coefficient of
5 mV/K and is 1.49 V (nominal) at 125°C. The comparators
compare VPTAT with the externally set temperature trip points
and generate an open-collector output signal when one of their
respective thresholds has been exceeded.
The heat source for the TMP12 is an on-chip 100 Ω low
tempco thin-film resistor. When connected to a 5 V source, this
resistor dissipates:
2
PD =
V
R
52 V
100 Ω
= 0.25 W ,=
which generates a temperature rise of about 32°C in still air for
the SO packaged device. With an airflow of 450 feet per minute
(FPM), the temperature rise is about 22°C. By selecting a temperature setpoint between these two values, the TMP12 can provide
a logic-level indication of problems in the cooling system.
A proprietary, low tempco thin-film resistor process, in conjunction with production laser trimming, enables the TMP12 to
provide a temperature accuracy of 63°C (typ) over the rated
temperature range. The open-collector outputs are capable of
sinking 20 mA, allowing the TMP12 to drive small control relays directly. Operating from a single 15 V supply, the quiescent
current is only 600 µA (max), without the heater resistor current.
Temperature Package Package
Model/Grade Range
1
Description Option
TMP12FP XIND Plastic DIP N-8
TMP12FS XIND SOIC SO-8
TMP12GBC 125°C Die
NOTE
1
XIND = 240°C to 1125°C
REV. 0–4–
TMP12
35
V = 5V
SO–8 SOLDERED TO .5 "
30
25
a. 0 FPM
20
b. 250 FPM
c. 450 FPM
15
d. 600 FPM
10
5
0
JUNCTION TEMPERATURE RISE ABOVE AMBIENT – °C
0
HEATER RESISTOR POWER DISSIPATION – mW
50 100 150 200
.3" Cu PCB
a
AIR FLOW RATES
b
d
c
250
Figure 1. SOIC Junction Temperature Rise vs. Heater
Dissipation
25
V = 5V
PDIP SOLDERED TO 2"
20
a. 0 FPM
b. 250 FPM
15
c. 450 FPM
d. 600 FPM
10
5
0
JUNCTION TEMPERATURE RISE ABOVE AMBIENT – °C
0 25050 100 150 200
HEATER RESISTOR POWER DISSIPATION – mW
1.31" Cu PCB
b
a
AIR FLOW RATES
c
d
140
TRANSITION FROM 100°C STIRRED
BATH TO FORCED
120
V = 5V, NO LOAD, HEATER OFF
SO–8 SOLDERED TO .5" .3" Cu PCB
100
PDIP SOLDERED TO 2" 1.31" Cu PCB
80
60
TIME CONSTANT – sec
40
20
0
0 700100
25°C AIR
a. PDIP PCB
b. SOIC PCB
a
b
200 300 400 500 600
AIR VELOCITY – FPM
Figure 4. Package Thermal Time Constant in Forced Air
120
TRANSITION FROM STILL 25°C
110
100
90
80
70
60
50
40
30
JUNCTION TEMPERATURE – °C
20
10
0
02
AIR TO STIRRED
a
100°C BATH
V = 5V, NO LOAD, HEATER OFF
SO–8 SOLDERED TO .5" .3" Cu PCB
b
PDIP SOLDERED TO 2" 1.31" Cu PCB
a. SO–8 PCB
b. PDIP PCB
468101214161820
TIME – sec
Figure 2. PDIP Junction Temperature Rise vs. Heater
Dissipation
70
a. SO–8, HTR @ 5V
65
b. PDIP, HTR @ 5V
60
c. SO–8, HTR @ 3V
d. PDIP, HTR @ 3V
55
50
45
40
35
30
25
20
V = 5V RHEATER TO EXTERNAL
15
JUNCTION TEMPERATURE – °C
SUPPLY TURNED ON @ t = 5 sec
SO–8 SOLDERED TO .5" .3" COPPER PCB
10
PDIP SOLDERED TO 2" 1.31 COPPER PCB
5
0
0 10 20 30 40 50 60 70 80 90 100 110 120 130
TIME – sec
a
b
c
d
Figure 3. Junction Temperature Rise in Still Air
REV. 0 –5–
Figure 5. Thermal Response Time in Stirred Oil Bath
102
101.5
100.5
HEATER RESISTANCE – Ω
101
100
99.5
98.5
99
98
-75
-25 25 75 125 175
TEMPERATURE – °C
V+ = +5V
Figure 6. Heater Resistance vs. Temperature
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