ADT75 datasheet(22/24 Pages) AD

22 / 24 page

ADT75

Rev. 0 | Page 22 of 24

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.

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.

ADT75 Datasheet(PDF) 22 Page - Analog Devices