Rainbow Electronics LM95010 - Manual (Page 18)

3.0 Applications Information
3.1 MOUNTING CONSIDERATIONS
The LM95010 can be applied easily in the same way as
other integrated-circuit temperature sensors. It can be glued
or cemented to a surface. The temperature that the
LM95010 is reading will typically be within +0.2 ˚C of the
surface temperature to which the LM95010’s leads are at-
tached to.
This presumes that the ambient air temperature is almost the
same as the surface temperature; if the air temperature were
much higher or lower than the surface temperature, the
actual temperature measured would be at an intermediate
temperature between the surface temperature and the air
temperature.
Alternatively, the LM95010 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
LM95010 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 tempera-
tures 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
LM95010 or its connections.
The thermal resistance junction to ambient ( θ
JA
) is the pa-
rameter used to calculate the rise of a device junction tem-
perature due to its power dissipation. For the LM95010 the
equation used to calculate the rise in the die temperature is
as follows: T
J
= T
A
+
θ
JA
x [(V + x I
Q
) + (V
OL
x I
OL
)]
where I
Q
is the quiescent current (500 µA typ.), V
OL
is the
logic "Low" output level of SWD, and I
OL
is the load current
on SWD. Since the LM95010’s junction temperature is the
actual temperature being measured care should be taken to
minimize the load current that the LM95010 is require to
drive. When mounted to a PCB, with 2 oz. copper foil, the
LM95010’s thermal resistance is typically 210 ˚C/W.
LM95010
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