SN54LS170 Datasheet, PDF (1/4 Pages) Motorola, Inc – 4 x 4 REGISTER FILE OPEN-COLLECTOR

4 x 4 REGISTER FILE
OPEN-COLLECTOR
The TTL / MSI SN54 / 74LS170 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.
Open-collector outputs make it possible to connect up to 128 outputs in a
wired-AND configuration 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 / 74LS670 provides a similar function to this device but it features
3-state outputs.
• Simultaneous Read/ Write Operation
• Expandable to 512 Words of n-Bits
• Typical Access Time of 20 ns
• Low Leakage Open-Collector Outputs for Expansion
• Typical Power Dissipation of 125 mW
CONNECTION DIAGRAM DIP (TOP VIEW)
VCC D1 WA WB EW ER Q1 Q2
16 15 14 13 12 11 10 9
1 2 3 4 56 78
D2 D3 D4 RB RA Q4 Q3 GND
NOTE:
The Flatpak version
has the same pinouts
(Connection Diagram) as
the Dual In-Line Package.
PIN NAMES
LOADING (Note a)
HIGH
LOW
D1 – D4
WA, WB
EW
RA, RB
ER
Q1 – Q4
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.
1.0 U.L.
Open-Collector
0.25 U.L.
0.25 U.L.
0.5 U.L.
0.25 U.L.
0.5 U.L.
5 (2.5) U.L.
NOTES:
a. 1 TTL Unit Load (U.L.) = 40 µA HIGH/1.6 mA LOW.
b. The Output LOW drive factor is 2.5 U.L. for Military (54) and 5 U.L. for Commercial (74)
b. Temperature Ranges. The Output HIGH drive must be supplied by an external resistor to VCC.
SN54/74LS170
4 x 4 REGISTER FILE
OPEN-COLLECTOR
LOW POWER SCHOTTKY
16
1
J SUFFIX
CERAMIC
CASE 620-09
16
1
N SUFFIX
PLASTIC
CASE 648-08
16
1
D SUFFIX
SOIC
CASE 751B-03
ORDERING INFORMATION
SN54LSXXXJ
SN74LSXXXN
SN74LSXXXD
Ceramic
Plastic
SOIC
LOGIC SYMBOL
12 15 1 2 3
14
13
WA EW
WB
D1 D2 D3 _D4
5 RA
4 RB ER Q1 Q2 Q3 Q4
11 10 9 7 6
VCC = PIN 16
GND = PIN 8
FAST AND LS TTL DATA
5-1