74HC670 查看數據表（PDF） - Philips Electronics
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74HC670 Datasheet PDF : 9 Pages
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Philips Semiconductors
4 x 4 register file; 3-state
PIN DESCRIPTION
PIN NO.
5, 4
8
10, 9, 7, 6
11
12
14, 13
15, 1, 2, 3
16
SYMBOL
RA, RB
GND
Q0 to Q3
RE
WE
WA, WB
D0 to D3
VCC
NAME AND FUNCTION
read address inputs
ground (0 V)
data outputs
3-state output read enable input (active LOW)
write enable input (active LOW)
write address inputs
data inputs
positive supply voltage
Product specification
74HC/HCT670
Fig.1 Pin configuration.
Fig.2 Logic symbol.
Fig.3 IEC logic symbol.
Fig.4 Functional diagram.
WRITE MODE SELECT TABLE
OPERATING
MODE
write data
data latched
INPUTS
WE Dn
LL
LH
HX
INTERNAL
LATCHES(1)
L
H
no change
Note
1. The write address (WA and WB) to the
“internal latches” must be stable while WE is
LOW for conventional operation.
READ MODE SELECT TABLE
OPERATING
MODE
read
disabled
INPUTS
OUTPUT
RE INTERNAL LATCHES(1)
Qn
L
L
L
L
H
H
H
X
Z
Notes
1. The selection of the “internal latches” by read address
(RA and RB) are not constrained by WE or RE operation.
H = HIGH voltage level
L = LOW voltage level
X = don’t care
Z = high impedance OFF-state
December 1990
3
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