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參數(shù)資料
| 型號： | TMP3567 |
| 元件分類： | TVS-瞬態(tài)抑制二極管 |
| 英文描述： | Transient Voltage Suppressor Diodes |
| 文件頁數(shù)： | 7/16頁 |
| 文件大小： | 476K |
| 代理商： | TMP3567 |
REV. C
TMP35/TMP36/TMP37
–7–
APPLICATIONS SECTION
Shutdown Operation
All TMP3x devices include a shutdown capability that reduces the
power supply drain to less than 0.5
μ
A maximum. This feature,
available only in the SOIC-8 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 TMP3x at the
SHUTDOWN
pin, a pull-up current
source to V
IN
is connected. This permits the
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
the output stage OFF. During shutdown, the output of the
temperature sensors becomes a high impedance state where the
potential of the output pin would then be determined by external
circuitry. If the shutdown feature is not used, it is recommended
that the
SHUTDOWN
pin be connected to V
IN
(Pin 8 on the
SOIC-8, Pin 2 on the SOT-23).
The shutdown response time of these temperature sensors is
illustrated in TPCs 9, 10, and 11.
Mounting Considerations
If the TMP3x 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 to +125
°
C. Properly cemented or
glued to the surface of the medium, these sensors will be within
0.01
°
C of the surface temperature. Caution should be exercised,
especially with TO-92 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
temperature sensor and the hookup wires with a bead of
thermally conductive epoxy. This will ensure that the TMP3x
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 non-
conductive epoxy paints or dip or any one of many printed circuit
board coatings and varnishes.
Thermal Environment Effects
The thermal environment in which the TMP3x sensors are used
determines two important characteristics: self-heating effects
and thermal response time. Illustrated in Figure 3 is a thermal
model of the TMP3x temperature sensors that is useful in
understanding these characteristics.
T
J
JC
T
C
CA
C
CH
C
C
P
D
T
A
Figure 3. Thermal Circuit Model
In the TO-92 package, the thermal resistance junction-to-case,
θ
JC
, is 120
°
C/W. The thermal resistance case-to-ambient,
θ
CA
, is
the difference between
θ
JA
and
θ
JC
, and is determined by the
characteristics of the thermal connection. The temperature
sensor’s power dissipation, represented by
P
D
, is the product of
the total voltage across the device and its total supply current
(including any current delivered to the load). The rise in die
temperature above the medium’s ambient temperature is given by:
(
Thus, the die temperature rise of a TMP35 “RT” 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 TMP3x sensors to a step change
in the temperature is determined by the thermal resistances and
the thermal capacities of the die, C
CH
, and the case, C
C
. The
thermal capacity of the case, C
C
, varies with the measurement
medium since it includes anything in direct contact with the
package. In all practical cases, the thermal capacity of the case is
the limiting factor in the thermal response time of the sensor
and can be represented by a single-pole RC time constant
response. TPCs 12 and 14 illustrate the thermal response time
of the TMP3x 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 “S” package sensor mounted onto a 0.5"
by 0.3" PCB is less than 50 sec in air, whereas in a stirred oil
bath, the time constant is less than 3 seconds.
Basic Temperature Sensor Connections
Figure 4 illustrates the basic circuit configuration for the
TMP3x family of temperature sensors. The table shown in the
figure illustrates the pin assignments of the temperature sensors
for the three package types. For the SOT-23, Pin 3 is labeled as
“NC” as are Pins 2, 3, 6, and 7 on the SOIC-8 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 the SOIC-8 package, the
SHUTDOWN
pin
should be connected to V
S
.
T
P
T
D
C
CA
A
J
J
=
×
+
)
+
θ
θ
2.7V < Vs < 5.5V
V
OUT
TMP3x
0.1 F
Vs
GND
PACKAGE
V
S
GND
V
OUT
SHDN
SOIC-8
SOT-23-5
TO-92
8
2
1
4
5
3
1
1
2
5
4
NA
PIN ASSIGNMENTS
SHDN
Figure 4. Basic Temperature Sensor Circuit Configuration
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| TMP35FS | 制造商:Analog Devices 功能描述:Temp Sensor Analog(Voltage) Serial (2-Wire) 8-Pin SOIC N 制造商:Rochester Electronics LLC 功能描述:3V TEMPERATURE SENSOR - Bulk |
| TMP35FS-REEL | 制造商:Analog Devices 功能描述:Temp Sensor Analog Serial (2-Wire) 8-Pin SOIC N T/R 制造商:Rochester Electronics LLC 功能描述:3V TEMPERATURE SENSOR TAPE & REEL - Tape and Reel |
| TMP35FSZ | 制造商:Analog Devices 功能描述:Temperature Sensor IC |
| TMP35FSZ-REEL | 制造商:Analog Devices 功能描述:TEMP SENSOR ANLG SERL 8SOIC N - Tape and Reel |
| TMP35FT9 | 制造商:Rochester Electronics LLC 功能描述:3V TEMPERATURE SENSOR - Bulk 制造商:Analog Devices 功能描述: |
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