SN54/74LS670
4 x 4 REGISTER FILE
WITH 3-STATE OUTPUTS
The TTL / MSI SN54 / 74LS670 is a high-speed, low-power 4 x 4 Register
File organized as four words by four bits. 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.
The SN54 / 74LS170 provides a similar function to this device but it features
open-collector outputs.
•
•
•
•
•
Simultaneous Read / Write Operation
Expandable to 512 Words by n-Bits
Typical Access Time to 20 ns
3-State Outputs for Expansion
Typical Power Dissipation of 125 mW
4 x 4 REGISTER FILE
WITH 3-STATE OUTPUTS
LOW POWER SCHOTTKY
J SUFFIX
CERAMIC
CASE 620-09
16
1
CONNECTION DIAGRAM DIP (TOP VIEW)
VCC
16
D1
15
WA
14
WB
13
EW
12
ER
11
Q1
Q2
10
9
N SUFFIX
PLASTIC
CASE 648-08
16
1
NOTE:
The Flatpak version
has the same pinouts
(Connection Diagram) as
the Dual In-Line Package.
D SUFFIX
SOIC
CASE 751B-03
16
1
1
D2
2
D3
3
D4
4
RB
5
RA
6
Q4
7
Q3
8
GND
ORDERING INFORMATION
PIN NAMES
HIGH
D1 – D4
WA, WB
EW
RA, RB
ER
Q 1 – Q4
SN54LSXXXJ
SN74LSXXXN
SN74LSXXXD
LOADING (Note a)
Data Inputs
Write Address Inputs
Write Enable (Active LOW) Input
Read Address Inputs
Read Enable (Active LOW) Input
Outputs (Note b)
0.5 U.L.
0.5 U.L.
1.0 U.L.
0.5 U.L.
1.5 U.L.
65 (25) U.L.
LOW
0.25 U.L.
0.25 U.L.
0.5 U.L.
0.25 U.L.
0.75 U.L.
15 (7.5) U.L.
NOTES:
a) 1 TTL Unit Load (U.L.) = 40 µA HIGH/1.6 mA LOW.
b) The Output LOW drive factor is 7.5 U.L. for Military (54) and 15 U.L. for Commercial
(74) Temperature Ranges. The Output HIGH drive factor is 25 U.L. for Military and
65 U.L. for Commercial Temperature Ranges.
Ceramic
Plastic
SOIC
LOGIC SYMBOL
12
14
13
5
4
15 1 2 3
WA EW D1 D2 D3 D4
WB
RA
RB ER Q1 Q2 Q3 Q4
11
10 9 7
VCC = PIN 16
GND = PIN 8
FAST AND LS TTL DATA
5-1
6
