LM35A National Semiconductor, LM35A Datasheet - Page 7

• Manufacturer Part Number: LM35A
• Description: Precision Centigrade Temperature Sensors
• Manufacturer: National Semiconductor

Typical Applications
CAPACITIVE LOADS
Like most micropower circuits, the LM35 has a limited ability
to drive heavy capacitive loads. The LM35 by itself is able to
drive 50 pf without special precautions. If heavier loads are
anticipated, it is easy to isolate or decouple the load with a
resistor; see Figure 3 . Or you can improve the tolerance of
capacitance with a series R-C damper from output to
ground; see Figure 4 .
When the LM35 is applied with a 200
shown in Figure 5 , Figure 6 or Figure 8 it is relatively immune
to wiring capacitance because the capacitance forms a by-
pass from ground to input, not on the output. However, as
with any linear circuit connected to wires in a hostile environ-
ment, its performance can be affected adversely by intense
electromagnetic sources such as relays, radio transmitters,
motors with arcing brushes, SCR transients, etc, as its wiring
can act as a receiving antenna and its internal junctions can
act as rectifiers. For best results in such cases, a bypass ca-
pacitor from V
75 in series with 0.2 or 1 µF from output to ground are often
useful. These are shown in Figure 13 , Figure 14 , and
Figure 16 .
FIGURE 3. LM35 with Decoupling from Capacitive Load
FIGURE 5. Two-Wire Remote Temperature Sensor
FIGURE 4. LM35 with R-C Damper
IN
to ground and a series R-C damper such as
(Grounded Sensor)
load resistor as
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FIGURE 7. Temperature Sensor, Single Supply, −55˚ to
FIGURE 9. 4-To-20 mA Current Source (0˚C to +100˚C)
FIGURE 6. Two-Wire Remote Temperature Sensor
FIGURE 8. Two-Wire Remote Temperature Sensor
(Output Referred to Ground)
(Output Referred to Ground)
+150˚C
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