74HC191U View Datasheet(PDF) - Philips Electronics
Part Name
Description
MFG CO.
74HC191U Datasheet PDF : 14 Pages
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Philips Semiconductors
Presettable synchronous 4-bit binary
up/down counter
Product specification
74HC/HCT191
Fig.4 Functional diagram.
FUNCTION TABLE
OPERATING MODE
parallel load
count up
count down
hold (do nothing)
INPUTS
PL
U/D
CE
CP
Dn
L
X
X
X
L
L
X
X
X
H
H
L
I
↑
X
H
H
I
↑
X
H
X
H
X
X
TC AND RC FUNCTION TABLE
INPUTS
TERMINAL COUNT STATE
U/D
CE
CP
Q0
Q1
Q2
Q3
H
H
X
H
H
L
H
X
H
H
L
L
H
H
L
H
X
L
L
H
H
X
L
L
H
L
L
L
H
H
H
H
H
H
L
L
L
L
L
L
Notes
1. H = HIGH voltage level
L = LOW voltage level
I = LOW voltage level one set-up time prior to the LOW-to-HIGH CP transition
X = don’t care
↑ = LOW-to-HIGH CP transition
= one LOW level pulse
= TC goes LOW on a LOW-to-HIGH CP transition
OUTPUTS
Qn
L
H
count up
count down
no change
OUTPUTS
TC
RC
L
H
H
H
L
H
H
H
December 1990
5
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