B

B

B

R

D =

R

R

2

1

2

+

o

A

A

f

R

R

C

1

2

1.44

((

2

) )

=

+

1

2

3

4

5

6

7

14

13

12

11

10

9

8

LM556

0.01 µF

10 µF

100 µF

0.01 µF

0.01 µF

LM556

SNAS549A – MARCH 2000 – REVISED OCTOBER 2015

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 LM556 timer can be used in various configurations. A typical application for the LM556 timer in astable

mode is to drive an audio device (such as a beeper) to provide a pulsed sound. This simple application can be

modified to fit any application requirement.

8.2 Typical Application

Figure 13. Typical Application

8.2.1 Design Requirements

The main design requirements for this application require setting one of the timers (Timer A in this case) to the

Equation 1:

(1)

The other design choice is to decide how often and long to produce the bleeping sound. This can be set by

(2)

capacitor.

10

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