LM35

+

OUT

HEAVY CAPACITIVE LOAD, WIRING, ETC.

TO A HIGH-IMPEDANCE LOAD

v

75

1 PF

0.01 PF BYPASS

OPTONAL

LM35

+

OUT

2 k

HEAVY CAPACITIVE LOAD, WIRING, ETC.

TO A HIGH-IMPEDANCE LOAD

v

LM35

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SNIS159C – AUGUST 1999 – REVISED JULY 2013

TYPICAL APPLICATIONS

Figure 14. LM35 with Decoupling from Capacitive Load

Figure 15. LM35 with R-C Damper

CAPACITIVE LOADS

Like most micropower circuits, the LM35 has a limited ability to drive heavy capacitive loads. The LM35 alone is

able to drive 50 pf without special precautions. If heavier loads are anticipated, isolating or decoupling the load

with a resistor is easy (see Figure 14). Or you can improve the tolerance of capacitance with a series R-C

damper from output to ground (see Figure 15).

When the LM35 is applied with a 200-W load resistor as shown in Figure 16, Figure 17, or Figure 19, the device

is relatively immune to wiring capacitance because the capacitance forms a bypass from ground to input and not

on the output. However, as with any linear circuit connected to wires in a hostile environment, performance is

affected adversely by intense electromagnetic sources such as relays, radio transmitters, motors with arcing

brushes, and SCR transients, as the wiring acts as a receiving antenna and the internal junctions act as

as 75 W, in series with 0.2 or 1

μF from output to ground are often useful. These are shown in Figure 24,

Figure 24, and Figure 27.

Copyright © 1999–2013, Texas Instruments Incorporated

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