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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.
Low Power Dissipation 100 mW Typical
High-Speed Count Frequency 30 MHz Typical
Fully Synchronous Operation
Full Carry Lookahead for Easy Cascading
Single Up/Down Control Input
Positive Edge-Trigger Operation
Input Clamp Diodes Limit High-Speed Termination Effects
NOTE:
The Flatpak version
has the same pinouts
(Connection Diagram) as
the Dual In-Line Package.
14
13
12
11
10
9
1
2
3
P0
4
5
P2
6
P3
7
16
15
8
VCC
U/D
TC
Q0
Q1
Q2
CET
Q3
PE
CP
P1
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
NOTES:
a. 1 TTL Unit Load (U.L.) = 40
μ
A 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.
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.
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
SN74LSXXXN
SN74LSXXXD
Ceramic
Plastic
SOIC
16
1
D SUFFIX
SOIC
CASE 751B-03
LOGIC SYMBOL
9
3
4
5
6
7
10
2
15
14 13
12
11
PE P0P1
U/D
P2P3
CEP
CET
CP
Q0Q1Q2Q3
TC
VCC = PIN 16
GND = PIN 8
1