Datasheet

LM70

SNIS112G –JUNE 2000–REVISED MARCH 2013

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Application Hints

To get the expected results when measuring temperature with an integrated circuit temperature sensor like the

LM70, it is important to understand that the sensor measures its own die temperature. For the LM70, the best

thermal path between the die and the outside world is through the LM70's pins. In the VSSOP-8 package the

ground pin is connected to the back side of the LM70 die and thus has the most effect on the die temperature.

Although the other pins will also have some effect on the LM70die temperature and therefore should not be

discounted. The LM70 will provide an accurate measurement of the temperature of the printed circuit board on

which it is mounted, because the pins represent a good thermal path to the die. A less efficient thermal path

exists between the plastic package and the LM70 die. If the ambient air temperature is significantly different from

the printed circuit board temperature, it will have a small effect on the measured temperature.

In probe-type applications, the LM70 can be mounted inside a sealed-end metal tube, and can then be dipped

into a bath or screwed into a threaded hole in a tank. As with any IC, the LM70 and accompanying wiring and

circuits must be kept insulated and dry, to avoid leakage and corrosion. This is especially true if the circuit may

operate at cold temperatures where condensation can occur. Printed-circuit coatings and varnishes such as

Humiseal and epoxy paints or dips are often used to insure that moisture cannot corrode the LM70 or its

connections.

Typical Applications

Figure 15. Temperature Monitor Using Intel 196 Processor

Product Folder Links: LM70