Application Hints (Continued)
DS012893-18
FIGURE 3. Simplified Schematic
4.0 MOUNTING CONSIDERATIONS
As with any IC, the LM56 and accompanying wiring and cir-
cuits must be kept insulated and dry, to avoid leakage and
corrosion. This is especially true if the cirucit 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 ensure that moisture
cannot corrode the LM56 or its connections.
The majority of the temperature that the LM56 is measuring
is the temperature of its leads. Therefore, when the LM56 is
placed on a printed circuit board, it is not sensing the tem-
perature of the ambient air. It is actually sensing the tem-
perature difference of the air and the lands and printed circuit
board that the leads are attached to. The most accurate tem-
perature sensing is obtained when the ambient temperature
is equivalent to the LM56’s lead temperature.
9
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