Harman Kardon PA 2000, Service Manual

Page: 74 / 104

Quad buffer/line driver; 3-state 74HC/HCT125
PIN DESCRIPTION
PIN NO. SYMBOL NAME AND FUNCTION
1, 4, 10, 13 1OE to 4OE outputs enable inputs (active LOW)
2, 5, 9, 12 1A to 4A data inputs
3, 6, 8, 11 1Y to 4Y data outputs
7 GND ground (0 V)
14 V
CC
positive supply voltage
Fig.1 Pin configuration. Fig.2 Logic symbol. Fig.3 IEC logic symbol.
(a) (b)
Fig.4 Functional diagram. Fig.5 Logic diagram (one buffer).
FUNCTION TABLE
Note
1. H = HIGH voltage level
L = LOW voltage level
X = don’t care
Z = high impedance OFF-state
INPUTS OUTPUT
nOE nA nY
L
L
H
L
H
X
L
H
Z
PA2000/PA4000 harman/kardon
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