
5-1
FAST AND LS TTL DATA
SERIAL-IN PARALLEL-OUT 
SHIFT REGISTER
The SN54/74LS164 is a high speed 8-Bit Serial-In Parallel-Out Shift Register. Serial data is entered through a 2-Input AND gate synchronous with the 
LOW to HIGH transition of the clock. The device features an asynchronous 
Master Reset which clears the register setting all outputs LOW independent of 
the clock. It utilizes the Schottky diode clamped process to achieve high 
speeds and is fully compatible with all Motorola TTL products.
• Typical Shift Frequency of 35 MHz
• Asynchronous Master Reset
• Gated Serial Data Input
• Fully Synchronous Data Transfers
• Input Clamp Diodes Limit High Speed Termination Effects
• ESD > 3500 Volts
CONNECTION DIAGRAM DIP (TOP VIEW)
14 13 12 11 10 9
1 2 3 4 5 6
8
7
V
CCQ7Q6Q5Q4
MR
CP
A B Q0Q1Q2Q3GND
NOTE: 
The Flatpak version 
has the same pinouts 
(Connection Diagram) as 
the Dual In-Line Package.
PIN NAMES LOADING (Note a)
HIGH
LOW
A, B 
CP 
MR 
Q0–Q
7
Data Inputs 
Clock (Active HIGH Going Edge) Input 
Master Reset (Active LOW) Input 
Outputs (Note b)
0.5 U.L.
0.5 U.L.
0.5 U.L. 
10 U.L.
0.25 U.L.
0.25 U.L.
0.25 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)
Temperature Ranges.
SN54/74LS164
SERIAL-IN PARALLEL-OUT
SHIFT REGISTER
LOW POWER SCHOTTKY
J SUFFIX
CERAMIC
CASE 632-08
N SUFFIX
PLASTIC
CASE 646-06
14
1
14
1
ORDERING INFORMATION
SN54LSXXXJ Ceramic 
SN74LSXXXN Plastic 
SN74LSXXXD SOIC
14
1
D SUFFIX
SOIC
CASE 751A-02
LOGIC SYMBOL
1 
2
8
9 3 4 5 6 10 11 12 13
A 
B 
CP
LS164
8-BIT SHIFT REGISTER
MR Q0Q1Q2Q3Q4Q5Q6Q
7
VCC = PIN 14 
GND = PIN 7

5-2
FAST AND LS TTL DATA
SN54/74LS164
LOGIC DIAGRAM
Q
6
Q
7
A
B
Q
0
Q
1
Q
3
Q
2
Q
5
Q
4
MR
CP
D Q
C
D
D Q
C
D
D Q
C
D
D Q
C
D
D Q
C
D
D Q
C
D
D Q
C
D
D Q
C
D
63 4 5 11 1210 13
VCC = PIN 14 
GND = PIN 7
 = PIN NUMBERS
1 
2
8
9
FUNCTIONAL DESCRIPTION
The LS164 is an edge-triggered 8-bit shift register with serial data entry and an output from each of the eight stages. Data 
is entered serially through one of two inputs (A or B); either of 
these inputs can be used as an active HIGH Enable for data 
entry through the other input. An unused input must be tied 
HIGH, or both inputs connected together.
Each LOW-to-HIGH transition on the Clock (CP) input shifts 
data one place to the right and enters into Q0 the logical AND 
of the two data inputs (A•B) that existed before the rising clock 
edge. A LOW level on the Master Reset (MR
) input overrides 
all other inputs and clears the register asynchronously , forcing 
all Q outputs LOW.
MODE SELECT — TRUTH TABLE
MR A B Q
0
Q1–Q
7
Reset (Clear) L X X L L – L
H I I L q0– q
6
Shift H I h L q0– q
6
H h I L q0– q
6
H h h H q0– q
6
L (l) = LOW Voltage Levels 
H (h) = HIGH Voltage Levels 
X = Don’t Care 
qn = Lower case letters indicate the state of the referenced input or output one
qn = set-up time prior to the LOW to HIGH clock transition.
GUARANTEED OPERATING RANGES
Symbol Parameter Min Typ Max Unit
V
CC
Supply Voltage 54
74
4.5
4.75
5.0
5.0
5.5
5.25
V
T
A
Operating Ambient Temperature Range 54
74
–55
0
25 
25
125
70
°C
I
OH
Output Current — High 54, 74 –0.4 mA
I
OL
Output Current — Low 54
74
4.0
8.0
mA

5-3
FAST AND LS TTL DATA
SN54/74LS164
DC CHARACTERISTICS OVER OPERATING TEMPERATURE RANGE (unless otherwise specified)
V
IH
Input HIGH Voltage 2.0 V
Guaranteed Input HIGH Voltage for 
All Inputs
Guaranteed Input LOW Voltage for 
All Inputs
V
IK
Input Clamp Diode Voltage –0.65 –1.5 V VCC = MIN, IIN = –18 mA
CC
 = MIN, IOH = MAX, VIN = V
IH
VCC = MIN, IOH = MAX, VIN = V
IH
or VIL per Truth Table
54, 74 0.25 0.4 V IOL = 4.0 mA
74 0.35 0.5 V IOL = 8.0 mA
VIN = VIH or V
IL
per Truth Table
20 µA VCC = MAX, VIN = 2.7 V
0.1 mA VCC = MAX, VIN = 7.0 V
I
IL
Input LOW Current –0.4 mA VCC = MAX, VIN = 0.4 V
I
OS
Short Circuit Current (Note 1) –20 –100 mA VCC = MAX
I
CC
Power Supply Current 27 mA VCC = MAX
Note 1: Not more than one output should be shorted at a time, nor for more than 1 second.
AC CHARACTERISTICS (T
A
 = 25°C)
f
MAX
Maximum Clock Frequency 25 36
MHz
t
PHL
Propagation Delay 
MR
 to Output Q
24 36 ns
t
PLH
t
PHL
Propagation Delay 
Clock to Output Q
17 
21
27 
32
ns
AC SETUP REQUIREMENTS (T
A
 = 25°C)
t
W
CP, MR Pulse Width 20
ns
t
s
Data Setup Time 15
ns
t
h
Data Hold Time 5.0
ns
t
rec
MR to Clock Recovery Time 20
ns
Guaranteed Input LOW Voltage for
V
VCC = VCC MIN,
VCC = 5.0 V

5-4
FAST AND LS TTL DATA
SN54/74LS164
AC WAVEFORMS
*The shaded areas indicate when the input is permitted to change for predictable output performance.
Figure 1. Clock to Output Delays
and Clock Pulse Width
Figure 2. Master Reset Pulse Width,
Master Reset to Output Delay and
Master Reset to Clock Recovery Time
Figure 3. Data Setup and Hold Times
CONDITIONS: MR = H
1.3 V
1.3 V 1.3 V
1.3 V
1.3 V
1.3 V
1.3 V
1.3 V
1.3 V
t
PHL
t
PLH
CP
Q
CP
Q
MR
t
rec
t
W
t
PHL
t
W
I
/f
max
1.3 V
1.3 V
1.3 V
1.3 V
1.3 V
1.3 V 1.3 V
CP
D
Q
ts(H)
th(H)
ts(L)
th(L)
t
W
1/f
max
1.3 V
1.3 V*
1.3V