Philips hef4538b DATASHEETS
INTEGRATED CIRCUITS
DATA SH EET
For a complete data sheet, please also download:
•The IC04 LOCMOS HE4000B Logic
Family Specifications HEF, HEC
•The IC04 LOCMOS HE4000B Logic
Package Outlines/Information HEF, HEC
HEF4538B
MSI
Dual precision monostable
multivibrator
Product specification
File under Integrated Circuits, IC04
January 1995
Philips Semiconductors Product specification
Dual precision monostable multivibrator
DESCRIPTION
The HEF4538B is a dual retriggerable-resettable
monostable multivibrator. Each multivibrator has an active
LOW trigger/retrigger input (I0), an active HIGH
trigger/retrigger input (I1), an overriding active LOW direct
reset input (CD), an output (O) and its complement (O),
and two pins (CTC,
timing components Ctand Rt. Typical pulse width variation
over temperature range is ± 0,2%.
The HEF4538B may be triggered by either the positive or
the negative edges of the input pulse and will produce an
(1)
RCTC) for connecting the external
HEF4538B
MSI
accurate output pulse with a pulse width range of 10 µs to
infinity. The duration and accuracy of the output pulse are
determined by the external timing components C
The output pulse width (T) is equal to Rt× Ct. The linear
design techniques in LOCMOS guarantee precise control
of the output pulse width.
A LOW level at CDterminates the output pulse
immediately. Schmitt-trigger action in the trigger inputs
makes the circuit highly tolerant to slower rise and fall
times.
and Rt.
t
Fig.2 Pinning diagram.
HEF4538BP(N): 16-lead DIL; plastic (SOT38-1)
HEF4538BD(F): 16-lead DIL; ceramic (cerdip) (SOT74)
HEF4538BT(D): 16-lead SO; plastic (SOT109-1)
( ): Package Designator North America
PINNING
I
0A,I0B
, I
I
1A
1B
CDA, C
, O
O
A
OA, O
C
TC A
RC
TC A
B
B
, C
DB
TC B
, RC
input (HIGH to LOW triggered)
input (LOW to HIGH triggered)
direct reset input (active LOW)
output
complementary output (active LOW)
external capacitor connections
external capacitor/ resistor
TC B
(1)
connections
Note
1. Always connected to ground.
Fig.1 Functional diagram.
January 1995 2
FAMILY DATA, I
LIMITS category MSI
DD
See Family specifications.
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January 1995 3
Philips Semiconductors Product specification
Dual precision monostable multivibrator
Fig.3 Logic diagram.
HEF4538B
MSI
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