ADT75 Analog Devices, Inc., ADT75 Datasheet - Page 22

• Manufacturer Part Number: ADT75
• Description: ?1?c Accurate, 12-bit Digital Temperature Sensor
• Manufacturer: Analog Devices, Inc.

ADT75
TEMPERATURE MONITORING
The ADT75 is ideal for monitoring the thermal environment
within electronic equipment. For example, the surface-mounted
package accurately reflects the exact thermal conditions that
affect nearby integrated circuits.
The ADT75 measures and converts the temperature at the
surface of its own semiconductor chip. When the ADT75 is
used to measure the temperature of a nearby heat source, the
thermal impedance between the heat source and the ADT75
must be considered. Often, a thermocouple or other
temperature sensor is used to measure the temperature of the
source, while the temperature is monitored by reading back
from the ADT75 temperature value register.
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Once the thermal impedance is determined, the temperature of
the heat source can be inferred from the ADT75 output. As
much as 60% of the heat transferred from the heat source to the
thermal sensor on the ADT75 die is discharged via the copper
tracks, the package pins, and the bond pads. Of the pins on the
ADT75, the GND pin transfers most of the heat. Therefore, to
measure the temperature of a heat source it is recommended
that the thermal resistance between the ADT75 GND pin and
the GND of the heat source is reduced as much as possible.
For example, use the ADT75’s unique properties to monitor a
high-power dissipation microprocessor. The ADT75 device, in a
surface-mounted package, is mounted directly beneath the
microprocessor’s pin grid array (PGA) package. The ADT75
produces a linear temperature output while needing only two
I/O pins and requiring no external characterization.