HD74AC670
4
4 Register File with 3-State Output
Description
The HD74AC670 contains 16 high speed, low power, transparent D-type latches arranged as four words of
four bits each, to function as a 4
4 register file. Separate read and write inputs, both address and enable,
allow simultaneous read and write operation. The 3-state outputs make it possible to connect up to 128
outputs to increase the word capacity up to 512 words. Any number of these devices can be operated in
parallel to generate an n-bit length.
Features
3-State Outputs Drive Bus Lines or Buffer Memory Address Registers
Outputs Source/Sink 24 mA
Pin Arrangement
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
D
2
D
3
D
4
RA
1
RA
0
O
3
O
4
GND
V
CC
D
1
WA
0
WA
1
WE
OE
O
1
O
2
(Top view)
HD74AC670
4
Logic Diagram
G
D
Q
G
D
Q
G
D
Q
G
D
Q
O
1
D
1
G
D
Q
G
D
Q
G
D
Q
G
D
Q
O
2
D
2
G
D
Q
G
D
Q
G
D
Q
G
D
Q
O
3
D
3
G
D
Q
G
D
Q
G
D
Q
G
D
Q
O
4
D
4
Word
0
Word
1
Word
2
Word
3
WE
WA
1
WA
0
RA
1
OE
RA
0
DC Characteristics (unless otherwise specified)
Item
Symbol
Max
Unit
Condition
Maximum quiescent supply current
I
CC
80
A
V
IN
= V
CC
or ground, V
CC
= 5.5 V,
Ta = Worst case
Maximum quiescent supply current
I
CC
8.0
A
V
IN
= V
CC
or ground, V
CC
= 5.5 V,
Ta = 25
C
HD74AC670
5
AC Characteristics: HD74AC670
Ta = +25
C
C
L
= 50 pF
Ta = 40
C to +85
C
C
L
= 50 pF
Item
Symbol
V
CC
(V)*
1
Min
Typ
Max
Min
Max
Unit
Propagation delay
t
PLH
3.3
1.0
14.0
17.5
1.0
19.0
ns
W
E
to O
n
5.0
1.0
11.5
13.5
1.0
15.0
Propagation delay
t
PHL
3.3
1.0
13.5
17.0
1.0
18.5
ns
W
E
to O
n
5.0
1.0
11.0
13.0
1.0
14.5
Propagation delay
t
PLH
3.3
1.0
12.5
15.5
1.0
17.0
ns
R
A1
or R
A0
to O
n
5.0
1.0
10.0
12.0
1.0
13.0
Propagation delay
t
PHL
3.3
1.0
12.5
15.5
1.0
17.0
ns
R
A1
or R
A0
to O
n
5.0
1.0
10.0
12.0
1.0
13.0
Propagation delay
t
PLH
3.3
1.0
12.0
15.0
1.0
16.5
ns
Data to O
n
5.0
1.0
9.5
11.5
1.0
12.5
Propagation delay
t
PHL
3.3
1.0
11.5
14.5
1.0
16.0
ns
Data to O
n
5.0
1.0
9.0
11.0
1.0
12.0
Enable time
t
PZH
3.3
1.0
8.0
11.0
1.0
12.0
ns
OE
to O
n
5.0
1.0
6.0
8.5
1.0
9.5
Enable time
t
PZL
3.3
1.0
10.0
12.0
1.0
13.0
ns
OE
to O
n
5.0
1.0
7.5
9.5
1.0
10.5
Disable time
t
PHZ
3.3
1.0
8.0
11.0
1.0
12.0
ns
OE
to O
n
5.0
1.0
6.0
8.5
1.0
9.5
Disable time
t
PLZ
3.3
1.0
9.0
11.5
1.0
12.5
ns
OE
to O
n
5.0
1.0
7.0
9.0
1.0
10.0
Note:
1. Voltage Range 3.3 is 3.3 V
0.3 V
Voltage Range 5.0 is 5.0 V
0.5 V