NOTES:

tn = bit time before enable

negative-going transition

tn+1 = bit time after enable

negative-going transition

5-1

FAST AND LS TTL DATA

4-BIT D LATCH

The TTL/MSI SN54 / 74LS75 and SN54 / 74LS77 are latches used as tem-

porary storage for binary information between processing units and input /out-

put or indicator units. Information present at a data (D) input is transferred to

the Q output when the Enable is HIGH and the Q output will follow the data

input as long as the Enable remains HIGH. When the Enable goes LOW, the

information (that was present at the data input at the time the transition oc-

curred) is retained at the Q output until the Enable is permitted to go HIGH.

The SN54 / 74LS75 features complementary Q and Q output from a 4-bit

latch and is available in the 16-pin packages. For higher component density

applications the SN54 / 74LS77 4-bit latch is available in the 14-pin package

with Q outputs omitted.

14

13

12

11

10

9

1

2345

6

7

16

15

8

CONNECTION DIAGRAMS DIP (TOP VIEW)

SN54 / 74LS75

14

13

12

11

10

9

123456

8

7

SN54 / 74LS77

Q0

Q0

Q1

Q1

E0–1 GND

Q2

Q2

Q3

D0

D1

E2–3 VCC

D2

D3

Q3

Q0

Q1

E0–1 GND

NC

Q2

Q3

D0

D1

E2–3 VCC

D2

D3

NC

PIN NAMES

LOADING (Note a)

HIGH

LOW

D1–D4

E0–1

E2–3

Q1–Q4

Q1–Q4

Data Inputs

Enable Input Latches 0, 1

Enable Input Latches 2, 3

Latch Outputs (Note b)

Complimentary Latch Outputs (Note b)

0.5 U.L.

2.0 U.L.

2.0 U.L.

10 U.L.

10 U.L.

0.25 U.L.

1.0 U.L.

1.0 U.L.

5 (2.5) U.L.

5 (2.5) U.L.

NOTES:

a) 1 Unit Load (U.L.) = 40

µA HIGH.

b) The Output LOW drive factor is 2.5 U.L. for Military (54) and 5 U.L. for Commercial (74)

Temperature Ranges.

TRUTH TABLE

(Each latch)

tn

tn+1

D

H

L

Q

H

L

SN54/74LS75

SN54/74LS77

4-BIT D LATCH

LOW POWER SCHOTTKY

J SUFFIX

CERAMIC

CASE 620-09

N SUFFIX

PLASTIC

CASE 648-08

16

1

16

1

ORDERING INFORMATION

SN54LSXXJ

Ceramic

SN74LSXXN

Plastic

SN74LSXXD

SOIC

16

1

D SUFFIX

SOIC

CASE 751B-03

J SUFFIX

CERAMIC

CASE 632-08

N SUFFIX

PLASTIC

CASE 646-06

14

1

14

1

14

1

D SUFFIX

SOIC

CASE 751A-02