Datasheet

January 1995 8
Philips Semiconductors Product specification
Monostable/astable multivibrator
HEF4047B
MSI
1. Astable mode design information
a. Unit-to-unit transfer-voltage variations
The following analysis presents worst-case variations from unit-to-unit as a function of transfer-voltage (V
TR
) shift for free
running (astable) operation.
Values for t
A
are:
thus if t
A
= 4,40 R
t
C
t
is used, the maximum variation will be (+ 7,0%; −0,0%) at 10 V.
typ. : V
TR
= 0,5 V
DD
;t
A
= 4,40 R
t
C
t
V
DD
= 5 or 10 V
min. : V
TR
= 0,3 V
DD
;t
A
= 4,71 R
t
C
t
max.: V
TR
= 0,7 V
DD
;t
A
= 4,71 R
t
C
t
V
DD
= 15 V
min. : V
TR
=4 V; t
A
= 4,84 R
t
C
t
max.: V
TR
= 11 V; t
A
= 4,84 R
t
C
t
Fig.4 Astable mode waveforms.
t
1
R
t
C
t
In
V
TR
V
DD
V
TR
+
----------------------------
–=
t
2
R
t
C
t
In
V
DD
V
TR
–
2V
DD
V
TR
–
-------------------------------
–=
t
A
2t
1
t
2
+()2R
t
C
t
In
V
TR
()V
DD
V
TR
–()
V
DD
V
TR
+()2V
DD
V
TR
–()
-------------------------------------------------------------------------
, where t
A
Astable mode pulse width.=–==