
8D
7D
6D
5D
4D
3D
2D
1D
CLK
CLR
18
17
14
13
8
7
4
3
11
1
1D
C1
EN
8Q
7Q
6Q
5Q
4Q
3Q
2Q
1Q
19
16
15
12
6
5
2
9
logic symbol
†
†
This symbol is in accordance with ANSI/IEEE Std.
91-1984 and IEC Publication 617-12.
Pin numbers shown are for the DW, J, N, and W packages.
SN54273, SN54LS273, SN74273, SN74LS273
OCTAL D-TYPE FLIP-FLOP WITH CLEAR
SDLS090 – OCTOBER 1976 – REVISED MARCH 1988
Copyright 1988, Texas Instruments Incorporated
1
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
• Contains Eight Flip-Flops With Single-Rail
Outputs
• Buffered Clock and Direct Clear Inputs
• Individual Data Input to Each Flip-Flop
• Applications Include:
Buffer/Storage Registers
Shift Registers
Pattern Generators
description
These monolithic, positive-edge-triggered flipflops utilize TTL circuitry to implement D-type
flip-flop logic with a direct clear input.
Information at the D inputs meeting the setup time
requirements is transferred to the Q outputs on the
positive-going edge of the clock pulse. Clock
triggering occurs at a particular voltage level and
is not directly related to the transition time of the
positive-going pulse. When the clock input is at
either the high or low level, the D input signal has
no effect ar the output.
These flip-flops are guaranteed to respond to
clock frequencies ranging form 0 to 30 megahertz
while maximum clock frequency is typically 40
megahertz. Typical power dissipation is 39
milliwatts per flip-flop for the ′273 and 10 milliwatts
for the ′LS273.
FUNCTION TABLE
(each flip-flop)
INPUTS
OUTPUT
CLEAR CLOCK D
Q
L X X L
H ↑ HH
H ↑LL
HLXQ
0
SN54LS273 . . . FK PACKAGE
(TOP VIEW)
SN54273, SN74LS273 ...J OR W PACKAGE
SN74273 ...N PACKAGE
SN74LS273 . . . DW OR N PACKAGE
(TOP VIEW)
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
CLR
1Q
1D
2D
2Q
3Q
3D
4D
4Q
GND
V
CC
8Q
8D
7D
7Q
6Q
6D
5D
5Q
CLK
3212019
910111213
4
5
6
7
8
18
17
16
15
14
8D
7D
7Q
6Q
6D
2D
2Q
3Q
3D
4D
1D1QCLR5D8Q
4Q
GND
CLK
CC
V
5Q
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.

SN54273, SN54LS273, SN74273, SN74LS273
OCTAL D-TYPE FLIP-FLOP WITH CLEAR
SDLS090 – OCTOBER 1976 – REVISED MARCH 1988
2
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
schematics of inputs and outputs
V
CC
EQUIVALENT OF EACH INPUT
INPUT
R
eq
′273
Clear: Req = 3 kΩ NOM
Clock: Req = 6 kΩ NOM
All other inputs: Req = 8 kΩ NOM
V
CC
TYPICAL OF ALL OUTPUTS
100 Ω
NOM
OUTPUT
V
CC
EQUIVALENT OF EACH INPUT
INPUT
20 kΩ
NOM
′LS273
V
CC
TYPICAL OF ALL OUTPUTS
120 Ω NOM
OUTPUT
logic diagram (positive logic)
11
CLOCK
1
CLEAR
1D
1Q
R
C1
1D
1D
C1
R
2Q
2D
1D
C1
R
3Q
3D
1D
C1
R
4Q
4D
1D
C1
R
5Q
5D
1D
C1
R
6Q
6D
1D
C1
R
7Q
7D
1D
C1
R
8Q
8D
2
34
5
7
6
8
91312
14
15
17
16
18
19
Pin numbers shown are for the DW, J, N, and W packages.

SN54273, SN54LS273, SN74273, SN74LS273
OCTAL D-TYPE FLIP-FLOP WITH CLEAR
SDLS090 – OCTOBER 1976 – REVISED MARCH 1988
3
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
absolute maximum ratings over operating free-air temperature range (unless otherwise noted)
Supply voltage, V
CC
(see Note 1) 7 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Input voltage 5.5 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Operating free-air temperature range, T
A
: SN54273 –55°C to 125°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SN74273 0°C to 70°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Storage temperature range –65°C to 150°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
NOTE 1: Voltage values are with respect to network ground terminal.
recommended operating conditions
SN54273 SN74273
Supply voltage, V
CC
4.5 5 5.5 4.75 5 5.25 V
High-level output current, I
OH
–800 –800 µA
Low-level output current, I
OL
16 16 mA
Clock frequency, f
clock
0 30 0 30 MHz
Width of clock or clear pulse, t
w
16.5 16.5 ns
su
Clear inactive state 25↑ 25↑
Data hold time, t
h
5↑ 5↑ ns
Operating free-air temperature, T
A
–55 125 0 70 °C
↑The arrow indicates that the rising edge of the clock pulse is used for reference.
electrical characteristics over recommended operating free-air temperature range (unless
otherwise noted)
PARAMETER TEST CONDITIONS
†
MIN TYP‡MAX UNIT
V
IH
High-level input voltage 2 V
V
IL
Low-level input voltage 0.8 V
V
IK
Input clamp voltage VCC = MIN, II = –12 mA –1.5 V
V
OH
High-level output voltage
VCC = MIN,
VIL = 0.8 V,
VIH = 2 V,
IOH = –800 µA
2.4 3.4 V
V
OL
Low-level output voltage
VCC = MIN,
VIL = 0.8 V,
VIH = 2 V,
IOH = 16 mA
0.4 V
I
I
Input current at maximum input voltage VCC = MAX, VI = 5.5 V 1 mA
IIHHigh-level input current
IILLow-level input current
I
OS
Short-circuit output current
§
VCC = MAX –18 –57 mA
I
CC
Supply current VCC = MAX, See Note 2 62 94 mA
†
For conditions shown as MIN or MAX, use the appropriate value specified under recommended operating conditions.
‡
All typical values are at VCC = 5 V, TA = 25°C.
§
Not more than one output should be shorted at a time.
NOTE 2: With all outputs open and 4.5 V applied to all data and clear inputs, ICC is measured after a momentary ground, then 4.5 V , is applied
to clock.

SN54273, SN54LS273, SN74273, SN74LS273
OCTAL D-TYPE FLIP-FLOP WITH CLEAR
SDLS090 – OCTOBER 1976 – REVISED MARCH 1988
4
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
switching characteristics, VCC = 5 V, TA = 25°C
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
f
max
Maximum clock frequency
30 40 MHz
t
PHL
Propagation delay time, high-to-low-level output from clear
CL = 15 pF,
18 27 ns
t
PLH
Propagation delay time, low-to-high-level output from clock
,
See Note 3
17 27 ns
t
PHL
Propagation delay time, high-to-low-level output from clock
18 27 ns
NOTE 3: Load circuits and voltage waveforms are shown in Section 1.
absolute maximum ratings over operating free-air temperature range (unless otherwise noted)
Supply voltage, V
CC
(see Note 1) 7 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Input voltage 7 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Operating free-air temperature range, T
A
: SN54LS273 –55°C to 125°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SN74LS273 0°C to 70°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Storage temperature range –65°C to 150°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
NOTE 1: Voltage values are with respect to network ground terminal.
recommended operating conditions
SN54LS273 SN74LS273
Supply voltage, V
CC
4.5 5 5.5 4.75 5 5.25 V
High-level output current, I
OH
–400 –400 µA
Low-level output current, I
OL
4 8 mA
Clock frequency, f
clock
0 30 0 30 MHz
Width of clock or clear pulse, t
w
20 20 ns
su
Clear inactive state 25↑ 25↑
Data hold time, t
h
5↑ 5↑ ns
Operating free-air temperature, T
A
–55 125 0 70 °C
↑The arrow indicates that the rising edge of the clock pulse is used for reference.

SN54273, SN54LS273, SN74273, SN74LS273
OCTAL D-TYPE FLIP-FLOP WITH CLEAR
SDLS090 – OCTOBER 1976 – REVISED MARCH 1988
5
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
electrical characteristics over recommended operating free-air temperature range (unless
otherwise noted)
V
IH
High-level input voltage 2 2 V
V
IL
Low-level input voltage 0.7 0.8 V
V
IK
Input clamp voltage VCC = MIN, II = –18 mA –1.5 –1.5 V
V
OH
High-level output voltage
VCC = MIN,
VIL = VILmax,
VIH = 2 V,
IOH = –400 µA
2.5 3.4 2.7 3.4 V
= 2 V,
IOL = 4 mA 0.25 0.4 0.25 0.4
VOLLow-level output voltage
I
I
Input current at
maximum input voltage
VCC = MAX, VI = 7 V 0.1 0.1 mA
I
IH
High-level input current VCC = MAX, VI = 2.7 V 20 20 µA
I
IL
Low-level input current VCC = MAX, VI = 0.4 V –0.4 –0.4 mA
I
OS
Short-circuit output
current
§
VCC = MAX –20 –100 –20 –100 mA
I
CC
Supply current VCC = MAX, See Note 2 17 27 17 27 mA
†
For conditions shown as MIN or MAX, use the appropriate value specified under recommended operating conditions.
‡
All typical values are at VCC = 5 V, TA = 25°C.
§
Not more than one output should be shorted at a time and duration of short circuit should not exceed one second.
NOTE 2: With all outputs open and 4.5 V applied to all data and clear inputs, ICC is measured after a momentary ground, then 4.5 V , is applied
to clock.
switching characteristics, VCC = 5 V, TA = 25°C
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
f
max
Maximum clock frequency
30 40 MHz
t
PHL
Propagation delay time, high-to-low-level output from clear
CL = 15 pF,
18 27 ns
t
PLH
Propagation delay time, low-to-high-level output from clock
See Note 3
17 27 ns
t
PHL
Propagation delay time, high-to-low-level output from clock
18 27 ns
NOTE 3: Load circuits and voltage waveforms are shown in Section 1.

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