5-1

FAST AND LS TTL DATA

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.

NOTE:

The Flatpak version

has the same pinouts

(Connection Diagram) as

the Dual In-Line Package.

CONNECTION DIAGRAM DIP (TOP VIEW)

14

13

12

11

10

9

1

2

3

4

5

6

7

16

15

8

VCC

D2

D1

WA

WB

EW

Q1

ER

Q2

D3

D4

RB

RA

Q4

Q3

GND

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)

SN54/74LS170

4 x 4 REGISTER FILE

OPEN-COLLECTOR

LOW POWER SCHOTTKY

J SUFFIX

CERAMIC

CASE 620-09

N SUFFIX

PLASTIC

CASE 648-08

16

1

16

1

ORDERING INFORMATION

SN54LSXXXJ

Ceramic

SN74LSXXXN

Plastic

SN74LSXXXD

SOIC

16

1

D SUFFIX

SOIC

CASE 751B-03

LOGIC SYMBOL

VCC = PIN 16

GND = PIN 8

12

15 1 2 3

13

14

4

5

11

10 9

7 6

EW

WA

WB

RB

RA

ER

D2 D3 D4

D1

Q4

Q3

Q1 Q2