5-1

FAST AND LS TTL DATA

BCD DECADE/MODULO

16 BINARY SYNCHRONOUS

BI-DIRECTIONAL COUNTERS

The SN54 / 74LS168 and SN54 / 74LS169 are fully synchronous 4-stage

up/down counters featuring a preset capability for programmable operation,

carry lookahead for easy cascading and a U / D input to control the direction

of counting. The SN54 / 74LS168 counts in a BCD decade (8, 4, 2, 1)

sequence, while the SN54 / 74LS169 operates in a Modulo 16 binary

sequence. All state changes, whether in counting or parallel loading, are

initiated by the LOW-to-HIGH transition of the clock.

NOTE:

The Flatpak version

has the same pinouts

(Connection Diagram) as

the Dual In-Line Package.

14

13

12

11

10

9

123

45

6

7

16

15

8

VCC

U/D

TC

Q0

Q1

Q2

CET

Q3

PE

CP

P0

P1

P2

P3

CEP GND

CONNECTION DIAGRAM DIP (TOP VIEW)

PIN NAMES

LOADING (Note a)

HIGH

LOW

CEP

CET

CP

PE

U/D

P0–P3

Q0–Q3

TC

Count Enable Parallel (Active LOW) Input

Count Enable Trickle (Active LOW) Input

Clock Pulse (Active positive going edge) Input

Parallel Enable (Active LOW) Input

Up-Down Count Control Input

Parallel Data Inputs

Flip-Flop Outputs

Terminal Count (Active LOW) Output

0.5 U.L.

1.0 U.L.

0.5 U.L.

0.5 U.L.

0.5 U.L.

0.5 U.L.

10 U.L.

10 U.L.

0.25 U.L.

0.5 U.L.

0.25 U.L.

0.25 U.L.

0.25 U.L.

0.25 U.L.

5 (2.5) 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)

SN54/74LS168

SN54/74LS169

BCD DECADE / MODULO

16 BINARY SYNCHRONOUS

BI-DIRECTIONAL COUNTERS

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

93

4

5

6

7

10

2

15

14 13 12 11

PE P0 P1 P2 P3

CEP

CET

CP

Q0 Q1 Q2 Q3

TC

VCC = PIN 16

GND = PIN 8

1

U/D