January 1995

8

Philips Semiconductors

Product specification

Monostable/astable multivibrator

HEF4047B

MSI

1. Astable mode design information

a. Unit-to-unit transfer-voltage variations

running (astable) operation.

Fig.4 Astable mode waveforms.

t

1

R

V

TR

V

DD

V

TR

+

----------------------------

–

=

t

2

R

V

DD

V

TR

–

2V

DD

V

TR

–

-------------------------------

–

=

t

A

2t

1

t

2

+

()

2R

V

TR

() V

DD

V

TR

–

()

V

DD

V

TR

+

() 2V

DD

V

TR

–

()

-------------------------------------------------------------------------

, where t

A

Astable mode pulse width.

=

–

=

=