Applications Information

Sensing Circuit Board and

Ambient Temperature

A temperature sensor IC like the MAX6613 that senses

its own die temperature must be mounted on, or close

to, the object whose temperature it is intended to mea-

sure. Because there is a good thermal path between

the package’s metal lead and the IC die, the MAX6613

can accurately measure the temperature of the circuit

board to which it is soldered. If the sensor is intended

to measure the temperature of a heat-generating com-

ponent on the circuit board, it should be mounted as

close as possible to that component and should share

supply and ground traces (if they are not noisy) with

that component where possible. This optimizes the

thermal connection from the component to the sensor.

The thermal path between the plastic package and the

die is not as good as the path through the lead, so the

MAX6613, like all temperature sensors in plastic pack-

ages, is less sensitive to the temperature of the sur-

rounding air than to the temperature of its leads. It can

be successfully used to sense ambient temperature if

the circuit board is designed to track the ambient tem-

perature.

As with any IC, the wiring and circuits must be kept

insulated and dry to avoid leakage and corrosion,

especially if the part is operated at cold temperatures

where condensation can occur.

The change in die temperature introduced by the part

due to self-heating is negligible.

Chip Information

TRANSISTOR COUNT: 307

PROCESS: BiCMOS

Low-Voltage Analog Temperature

Sensor in an SC70 Package

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