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

SNIS159F – AUGUST 1999 – REVISED JANUARY 2016

www.ti.com

8 Application and Implementation

NOTE

Information in the following applications sections is not part of the TI component

specification, and TI does not warrant its accuracy or completeness. TI’s customers are

responsible for determining suitability of components for their purposes. Customers should

validate and test their design implementation to confirm system functionality.

8.1 Application Information

The features of the LM35 make it suitable for many general temperature sensing applications. Multiple package

options expand on it's flexibility.

8.1.1 Capacitive Drive Capability

Like most micropower circuits, the LM35 device has a limited ability to drive heavy capacitive loads. Alone, the

LM35 device 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 12). The tolerance of capacitance can be improved with a

series R-C damper from output to ground (see Figure 13).

When the LM35 device is applied with a 200-

Ω 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), because the wiring acts as a receiving antenna and the internal

damper, such as 75

Ω in series with 0.2 or 1 μF from output to ground, are often useful. Examples are shown in

Figure 13, Figure 24, and Figure 25.

Figure 12. LM35 with Decoupling from Capacitive Load

Figure 13. LM35 with R-C Damper

14

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