Philips hef4518b 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
HEF4518B
MSI
Dual BCD counter
Product specification
File under Integrated Circuits, IC04
January 1995
Philips Semiconductors Product specification
Dual BCD counter
DESCRIPTION
T he HEF4518B is a dual 4-bit internally synchronous BCD
counter. The counter has an active HIGH clock input
(CP0) and an active LOW clock input (CP1), buffered
outputs from all four bit positions (O0to O3) and an active
HIGH overriding asynchronous master reset input (MR).
The counter advances on either the LOW to HIGH
transition of the CP0input if CP1is HIGH or the HIGH to
HEF4518B
MSI
LOW transition of the
or CP1may be used as the clock input to the counter and
the other clock input may be used as a clock enable input.
A HIGH on MR resets the counter (O0to O3= LOW)
independent of CP0, CP1.
Schmitt-trigger action in the clock input makes the circuit
highly tolerant to slower clock rise and fall times.
CP1input if CP0is LOW. Either CP
0
PINNING
,CP
CP
0A
CP1A, CP
MR
,MR
A
O
to O
0A
O
to O
0B
Fig.1 Functional diagram.
0B
1B
B
3A
3B
clock inputs (L to H triggered)
clock inputs (H to L triggered)
master reset inputs
outputs
outputs
Fig.2 Pinning diagram.
HEF4518BP(N): 16-lead DIL; plastic (SOT38-1)
HEF4518BD(F): 16-lead DIL; ceramic (cerdip) (SOT74)
HEF4518BT(D): 16-lead SO; plastic (SOT109-1)
( ): Package Designator North America
APPLICATION INFORMATION
Some examples of applications for the HEF4518B are:
• Multistage synchronous counting.
• Multistage asynchronous counting.
• Frequency dividers.
FAMILY DATA, I
LIMITS category MSI
DD
See Family Specifications
January 1995 2
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January 1995 3
Fig.3 Logic diagram (one counter).
Philips Semiconductors Product specification
Dual BCD counter
FUNCTION TABLE
CP
L L counter advances
X L no change
H L no change
XXHO
Notes
1. H = HIGH state (the more positive voltage)
L = LOW state (the less positive voltage)
X = state is immaterial
CP
0
H L counter advances
X L no change
L L no change
= positive-going transition
= negative-going transition
MR MODE
1
to O3= LOW
0
HEF4518B
MSI
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