TC72(2011) Ver la hoja de datos (PDF) - Microchip Technology
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TC72 Datasheet PDF : 28 Pages
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6.0 APPLICATIONS INFORMATION
The TC72 does not require any additional components
in order to measure temperature; however, it is
recommended that a decoupling capacitor of 0.1mF to
1mF be provided between the VDD and GND pins.
Although the current consumption of the TC72 is
modest (250 mA, typical), the TC72 contains an on
chip data acquisition with internal digital switching
circuitry. Thus, it is considered good design practice to
use an external decoupling capacitor with the sensor. A
high frequency ceramic capacitor should be used and
be located as close as possible to the IC power pins in
order to provide effective noise protection to the TC72.
The TC72 measures temperature by monitoring the
voltage of a diode located on the IC die. The IC pins of
the TC72 provide a low impedance thermal path
between the die and the PCB, allowing the TC72 to
effectively monitor the temperature of the PCB board.
The thermal path between the ambient air is not as
efficient because the plastic IC housing package
functions as a thermal insulator. Thus, the ambient air
temperature (assuming that a large temperature
gradient exists between the air and PCB) has only a
small effect on the temperature measured by the TC72.
Note that the exposed metal center pad on the bottom
of the DFN package is connected to the silicon
substrate. The center pad should be connected to
either the PCB ground plane or treated as a “No
Connect” pin. The mechanical dimensions of the center
pad are given in Section 7.0 “Packaging
Information” of this data sheet.
A potential for self-heating errors can exist if the TC72
SPI communication lines are heavily loaded. Typically,
the self-heating error is negligible because of the
relatively small current consumption of the TC72. A
temperature accuracy error of approximately +0.5°C
will result from self-heating if the SPI communication
pins sink/source the maximum current specified for the
TC72. Thus, to maximize temperature accuracy, the
output loading of the SPI signals should be minimized.
TC72
VDD
0.1µF
VDD
TC72
CE
SCK
SDO
SDI
GND
PICmicro®
MCU
I/O
SCK
SDI
SDO
FIGURE 6-1:
Typical Application.
© 2011 Microchip Technology Inc.
DS21743B-page 17
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