OCTAL D FLIP-FLOP WITH CLEAR
The SN54 / 74LS273 is a high-speed 8-Bit Register. The register consists of
eight D-Type Flip-Flops with a Common Clock and an asynchronous active
LOW Master Reset. This device is supplied in a 20-pin package featuring 0.3
inch lead spacing.
SN54/74LS273
•
•
•
•
8-Bit High Speed Register
Parallel Register
Common Clock and Master Reset
Input Clamp Diodes Limit High-Speed Termination Effects
CONNECTION DIAGRAM DIP
(TOP VIEW)
VCC Q7
20 19
D7
18
D6
17
Q6
16
Q5
15
D5
14
D
4
13
Q4
12
CP
11
OCTAL D FLIP-FLOP
WITH CLEAR
LOW POWER SCHOTTKY
20
1
J SUFFIX
CERAMIC
CASE 732-03
1
MR
PIN NAMES
2
Q0
3
D0
4
D1
5
Q1
6
Q2
7
D2
8
D3
9
Q3
10
GND
20
1
N SUFFIX
PLASTIC
CASE 738-03
LOADING
(Note a)
HIGH
LOW
0.25 U.L.
0.25 U.L.
0.25 U.L.
5 (2.5) U.L.
CP
D0 – D7
MR
Q0 – Q7
Clock (Active HIGH Going Edge) Input
Data Inputs
Master Reset (Active LOW) Input
Register Outputs (Note b)
0.5 U.L.
0.5 U.L.
0.5 U.L.
10 U.L.
20
1
DW SUFFIX
SOIC
CASE 751D-03
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.
ORDERING INFORMATION
SN54LSXXXJ
Ceramic
SN74LSXXXN Plastic
SN74LSXXXDW SOIC
TRUTH TABLE
MR
L
H
H
CP
X
Dx
X
H
L
Qx
L
H
L
H = HIGH Logic Level
L = LOW Logic Level
X = Immaterial
LOGIC DIAGRAM
11
3
4
7
8
13
14
17
18
D0
D1
D2
D3
D4
D5
D6
D7
CP
CP D
CD Q
CP D
CD Q
CP D
CD Q
CP D
CD Q
CP D
CD Q
CP D
CD Q
CP D
CD Q
CP D
CD Q
1
MR
VCC = PIN 20
GND = PIN 10
= PIN NUMBERS
Q0
2
Q1
5
Q2
6
Q3
9
Q4
12
Q5
15
Q6
16
Q7
19
FAST AND LS TTL DATA
5-1
SN54/74LS273
FUNCTIONAL DESCRIPTION
The SN54 / 74LS273 is an 8-Bit Parallel Register with a
common Clock and common Master Reset.
When the MR input is LOW, the Q outputs are LOW,
independent of the other inputs. Information meeting the setup
and hold time requirements of the D inputs is transferred to the
Q outputs on the LOW-to-HIGH transition of the clock input.
GUARANTEED OPERATING RANGES
Symbol
VCC
TA
IOH
IOL
Supply Voltage
Operating Ambient Temperature Range
Output Current — High
Output Current — Low
Parameter
54
74
54
74
54, 74
54
74
Min
4.5
4.75
– 55
0
Typ
5.0
5.0
25
25
Max
5.5
5.25
125
70
– 0.4
4.0
8.0
Unit
V
°C
mA
mA
DC CHARACTERISTICS OVER OPERATING TEMPERATURE RANGE
(unless otherwise specified)
Limits
Symbol
S b l
VIH
VIL
VIK
VOH
Parameter
P
Input HIGH Voltage
54
Input LOW Voltage
74
Input Clamp Diode Voltage
54
Output HIGH Voltage
74
54, 74
VOL
Output LOW Voltage
74
Input HIGH Current
0.1
Input LOW Current
Short Circuit Current (Note 1)
Power Supply Current
– 20
– 0.4
– 100
27
0.35
0.5
20
IIH
IIL
IOS
ICC
V
µA
mA
mA
mA
mA
2.7
3.5
0.25
0.4
V
V
2.5
– 0.65
3.5
0.8
– 1.5
V
V
Min
2.0
0.7
V
Typ
Max
Unit
U i
V
Test C di i
T
Conditions
Guaranteed Input HIGH Voltage for
All Inputs
Guaranteed Input LOW Voltage for
p
g
All Inputs
VCC = MIN, IIN = – 18 mA
VCC = MIN, IOH = MAX, VIN = VIH
,
,
or VIL per Truth Table
IOL = 4.0 mA
IOL = 8.0 mA
VCC = VCC MIN,
VIN = VIL or VIH
per Truth Table
VCC = MAX, VIN = 2.7 V
VCC = MAX, VIN = 7.0 V
VCC = MAX, VIN = 0.4 V
VCC = MAX
VCC = MAX
Note 1: Not more than one output should be shorted at a time, nor for more than 1 second.
AC CHARACTERISTICS
(TA = 25°C, VCC = 5.0 V)
Limits
Symbol
S b l
fMAX
tPHL
tPLH
tPHL
Parameter
P
Maximum Input Clock Frequency
Propagation Delay, MR to Q Output
Propagation Delay, Clock to Output
Min
30
Typ
40
18
17
18
27
27
27
Max
Unit
U i
MHz
ns
ns
Test C di i
T
Conditions
Figure 1
Figure 2
Figure 1
FAST AND LS TTL DATA
5-2
SN54/74LS273
AC SETUP REQUIREMENTS
(TA = 25°C, VCC = 5.0 V)
Limits
Symbol
S b l
tw
ts
th
trec
Parameter
P
Pulse Width, Clock or Clear
Data Setup Time
Hold Time
Recovery Time
Min
20
20
5.0
25
Typ
Max
Unit
U i
ns
ns
ns
ns
Test C di i
T
Conditions
Figure 1
Figure 1
Figure 1
Figure 2
AC WAVEFORMS
1/f max
tW
CP
1.3 V
ts(H)
D
*
1.3 V
tPLH
Qn
1.3 V
tPHL
*The shaded areas indicate when the input is permitted to
*change
for predictable output performance.
MR
1.3 V
th(L)
1.3 V
1.3 V
tPHL
1.3 V
tPLH
Qn
CP
Qn
tPLH
tW
1.3 V
trec
1.3 V
tPHL
1.3 V
1.3 V
1.3 V
1.3 V
1.3 V
th(H)
1.3 V
ts(L)
Figure 1. Clock to Output Delays, Clock Pulse Width,
Frequency, Setup and Hold Times Data to Clock
Figure 2. Master Reset to Output Delay, Master Reset
Pulse Width, and Master Reset Recovery Time
DEFINITION OF TERMS
SETUP TIME (ts) — is defined as the minimum time required
for the correct logic level to be present at the logic input prior to
the clock transition from LOW-to-HIGH in order to be recog-
nized and transferred to the outputs.
HOLD TIME (th) — is defined as the minimum time following
the clock transition from LOW-to-HIGH that the logic level
must be maintained at the input in order to ensure continued
recognition. A negative HOLD TIME indicates that the correct
logic level may be released prior to the clock transition from
LOW-to-HIGH and still be recognized.
RECOVERY TIME (trec) — is defined as the minimum time
required between the end of the reset pulse and the clock
transition from LOW-to-HIGH in order to recognize and
transfer HIGH data to the Q outputs.
FAST AND LS TTL DATA
5-3
嵌入式系统
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