Philips Semiconductors
Product specification
Dual retriggerable monostable
multivibrator with reset
FUNCTION TABLE
INPUTS
nR
D
L
X
X
H
H
↑
Note
1. If the monostable was triggered
before this condition was
established, the pulse will
continue as programmed.
nA
X
H
X
L
↓
L
nB
X
X
L
↑
H
H
L
L
(1)
L
(1)
OUTPUTS
nQ
nQ
H
H
(1)
H
(1)
H
L
X
↑
↓
74HC/HCT123
= HIGH voltage level
= LOW voltage level
= don’t care
= LOW-to-HIGH transition
= HIGH-to-LOW transition
= one HIGH level output pulse
= one LOW level output pulse
Fig.4 Functional diagram.
(1) For minimum noise generation,
it is recommended to ground pins 6 (2C
EXT
)
and 14 (1C
EXT
) externally to pin 8 (GND).
Fig.5 Logic diagram.
1998 Jul 08
4