FM20 View Datasheet(PDF) - Fairchild Semiconductor
Part Name
Description
Manufacturer
FM20 Datasheet PDF : 9 Pages
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FM20
Typical Performance Characteristics
PRODUCT SPECIFICATION
12
11
10
9
8
7
6
-50
-25
VDD = +5V
0
25
50
75
Temperature (°C)
100
125
Figure 1. Quiescent Current vs. Temperature
3
2
1
0
-1
-2
-3
-4
-5
-50
VDD =+5V
upper spec limit
lower spec limit
0
50
100
Temperature (°C)
Figure 2. Accuracy vs. Temperature
Applications Information
Mounting
The FM20 can be easily mounted by gluing or cementing it
to a surface. In this case, its temperature will be within about
0.2°C of the temperature of the surface it is attached to if the
ambient air temperature is almost the same as the surface
temperature. If the air temperature is much higher or lower
than the surface temperature, the actual temperature of the
FM20 die will be at an intermediate temperature between the
surface temperature and the air temperature.
To ensure good thermal conductivity, the backside of the
FM20 die is directly attached to the GND pin. The lands and
traces to the FM20 will, of course, be part of the printed
circuit board, which is the object whose temperature is being
measured. These printed circuit board lands and traces will
not cause the FM20’s temperature to deviate from the desired
temperature.
Alternatively, the FM20 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 FM20 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 condensa-
tion can occur. Printed-circuit coatings and varnishes such as
Humiseal and epoxy paint or dips can be used to ensure that
moisture cannot corrode the FM20 or its connections.
Loading
The FM20 will handle sizable capacitive loads up to 300pF
without any special considerations. In an extremely noisy
environment it may be advisable to add some filtering to
minimize noise in the output voltage. It is also recommended
that a 0.1µF bypass capacitor be added between the supply
voltage and ground. This is due to the instant current demand
caused by switching CMOS transistors. Normally it is un-
advisable to put a sufficiently large supply (particularly in
portable electronics) to be able to handle the dynamic cur-
rents of CMOS transistors. It is a much simpler solution to
use a bypass capacitor to sustain the supply voltage during
this short demand period.
4
REV. 1.0.6 1/9/03
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