LM56 National Semiconductor, LM56 Datasheet - Page 9

• Manufacturer Part Number: LM56
• Description: Dual Output Low Power Thermostat
• Manufacturer: National Semiconductor

Application Hints
4.0 MOUNTING CONSIDERATIONS
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.
(Continued)
FIGURE 3. Simplified Schematic
9
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
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.
temperatures
where
condensation
DS012893-18
can
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occur.