CGS74C2525
CGS74CT2525
CGS74C2526
CGS74CT2526
1-to-8 Minimum Skew Clock Driver
September 1995
CGS74C2525
CGS74CT2525
CGS74C2526
CGS74CT2526
1-to-8 Minimum Skew Clock Driver
The CGS ’C CT2525 is a minimum skew clock driver with
one input driving eight outputs specifically designed for sig-
nal generation and clock distribution applications The ’2525
is designed to distribute a single clock to eight separate
receivers with low skew across all outputs during both the
t
PLH
and t
PHL
transitions The ’2526 is similar to the ’2525
but contains a multiplexed clock input to allow for systems
with dual clock speeds or systems where a separate test
clock has been implemented
Features
Y
Y
Y
Y
Y
Y
Y
Y
Y
These CGS devices implement National’s FACT
TM
family
Ideal for signal generation and clock distribution
Guaranteed pin to pin and part to part skew
Multiplexed clock input (’2526)
Guaranteed 2 kV minimum ESD protection
Symmetric output current drive of 24 mA for I
OL
I
OH
’CT has TTL-compatible inputs
These products are identical to 74AC ACT2525 and
2526
Available as Mil Aero versions
54AC ACT2525
54AC ACT2526
Logic Symbols
’2525
Connection Diagrams
Pin Assignment
for DIP and SOIC
’2525
TL F 10684 – 1
’2526
TL F 10684 – 3
’2526
TL F 10684 – 2
TL F 10684 – 4
TRI-STATE is a registered trademark of National Semiconductor Corporation
FACT
TM
is a trademark of National Semiconductor Corporation
C
1996 National Semiconductor Corporation
TL F 10684
RRD-B30M106 Printed in U S A
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Functional Description
On the multiplexed clock device the SEL pin is used to
determine which CLKn input will have an active effect on
the outputs of the circuit When SEL
e
1 the CLK1 input is
selected and when SEL
e
0 the CLK0 input is selected
The non-selected CLKn input will not have any effect on the
logical output level of the circuit The output pins act as a
single entity and will follow the state of the CLK or
CLK1 CLK0 pins when either the multiplexed (’2526) or the
straight (’2525) clock distribution chip is selected
Pin Description
Pin Names
CLK
CLK0 CLK1
O
0
–O
7
SEL
Description
Clock Input (’2525)
Clock Inputs (’2526)
Outputs
Clock Select (’2526)
Truth Tables
’2525
Inputs
CLK
L
H
Outputs
O
0
–O
7
L
H
’2526
Inputs
CLK0
L
H
X
X
CLK1
X
X
L
H
SEL
L
L
H
H
Outputs
O
0
– O
7
L
H
L
H
L
e
Low Voltage Level
H
e
High Voltage Level
X
e
Immaterial
’2525
’2526
TL F 10684 –7
TL F 10684 – 8
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2
Absolute Maximum Ratings
(Note 1)
If Military Aerospace specified devices are required
please contact the National Semiconductor Sales
Office Distributors for availability and specifications
b
0 5V to
a
7 0V
Supply Voltage (V
CC
)
DC Input Diode Current (I
IK
)
V
I
e b
0 5V
V
I
e
V
CC
a
0 5V
DC Input Voltage (V
I
)
DC Output Diode Current (I
OK
)
V
O
e
0 5V
V
O
e
V
CC
a
0 5V
DC Output Voltage (V
O
)
DC Output Source
or Sink Current (I
O
)
DC V
CC
or Ground Current
per Output Pin (I
CC
or I
GND
)
Storage Temperature (T
STG
)
Junction Temperature (i
JA
)
Plastic (N) 14-Lead
Plastic (M) 14-Lead
Plastic (N) 16-Lead
Plastic (M) 16-Lead
b
20 mA
a
0 2 mA
b
0 5V to (V
CC
a
0 5V)
b
20 mA
a
20 mA
b
0 5V to (V
CC
a
0 5V)
g
50 mA
g
50 MA
Recommended Operating
Conditions
Supply Voltage (V
CC
)
‘C’
‘CT’
Input Voltage (V
I
)
Output Voltage (V
O
)
Operating Temperature (T
A
)
CGS74C CT
54AC ACT
Input Rise and Fall Times Devices
(30% to 70% of V
CC
)
V
CC
e
3 3V
4 5V
5 5V
Input Rise and Fall Times Devices
(0 8V to 2 0V)
2 0V to 6 0V
4 5V to 5 5V
0V to V
CC
0V to V
CC
b
40 C to
a
85 C
b
55 C to
a
125 C
10 5 ns max
14 4 ns max
17 6 ns max
9 6 ns max
b
65 C to
a
150 C
102
128
97
124
C
C
C
C
W
W
W
W
Note 1
Absolute maximum ratings are those values beyond which damage
to the device may occur The databook specifications should be met without
exception to ensure that the system design is reliable over its power supply
temperature and output input loading variables National does not recom-
mend operation of CGS circuits outside databook specifications
DC Electrical Characteristics for CGS74C and 54AC Family Devices
Over recommended operating conditions unless specified otherwise
CGS74C
Symbol
Parameter
V
CC
(V)
T
A
e a
25 C
Typ
V
IH
Minimum High Level
Input Voltage
Maximum Low Level
Input Voltage
Minimum High Level
Output Voltage
(Note 2)
30
45
55
30
45
55
30
45
55
30
45
55
V
OL
Maximum Low Level
Output Voltage
(Note 2)
30
45
55
30
45
55
0 002
0 001
0 001
15
2 25
2 75
15
2 25
2 75
2 99
4 49
5 49
21
3 15
3 85
09
1 35
1 65
29
44
54
2 56
3 86
4 86
01
01
01
0 36
0 36
0 36
54AC
T
A
e
b
55 C to
a
125 C
CGS74C
T
A
e
b
40 C to
a
85 C
Units
Conditions
Guaranteed Limits
21
3 15
3 85
09
1 35
1 65
29
44
54
24
37
47
01
01
01
0 40
0 50
0 50
21
3 15
3 85
09
1 35
1 65
29
44
54
2 46
3 76
4 76
01
01
01
0 44
0 44
0 44
V
V
OUT
e
0 1V
or V
CC
b
0 1V
V
OUT
e
0 1V
or V
CC
b
0 1V
I
OUT
e b
50
mA
V
V
IN
e
V
IL
or V
IH
b
12 mA
b
24 mA
I
OH
b
24 mA
I
OUT
e
50
mA
V
V
IN
e
V
IL
or V
IH
12 mA
24 mA
I
OL
24 mA
V
IL
V
V
OH
V
V
3
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DC Electrical Characteristics for CGS74C and 54AC Family Devices
(Continued)
Over recommended operating conditions unless specified otherwise
CGS74C
Symbol
Parameter
V
CC
(V)
T
A
e a
25 C
Typ
I
IN
Maximum Input
Leakage Current
(Note 3)
Minimum Dynamic
Output Current
(Note 4)
Maximum Quiescent
Supply Current
(Note 3)
55
55
55
g
0 1
54AC
T
A
e
b
55 C to
a
125 C
CGS74C
T
A
e
b
40 C to
a
85 C
Units
Conditions
Guaranteed Limits
g
1 0
g
1 0
mA
mA
mA
mA
V
I
e
V
CC
GND
V
OLD
e
1 65V Max
V
OHD
e
3 85V Min
V
IN
e
V
CC
or GND
I
OLD
I
OHD
I
CC
50
b
50
75
b
75
55
80
80 0
80 0
DC Electrical Characteristics for CGS74CT and 54ACT Family Devices
Over recommended operating conditions unless specified otherwise
CGS74CT
Symbol
Parameter
V
CC
(V)
T
A
e a
25 C
Typ
V
IH
V
IL
V
OH
Minimum High Level
Input Voltage
Maximum Low Level
Input Voltage
Minimum High Level
Output Voltage
(Note 2)
45
55
45
55
45
55
45
55
V
OL
Maximum Low Level
Output Voltage
(Note 2)
45
55
45
55
I
IN
I
CCT
I
OLD
I
OHD
I
CC
Maximum Input
Leakage Current
Maximum I
CC
Input
Minimum Dynamic
Output Current
(Note 4)
Maximum Quiescent
Supply Current
(Note 5)
55
55
55
55
06
0 001
0 001
15
15
15
15
4 49
5 49
20
20
08
08
44
54
3 86
4 86
01
01
0 36
0 36
g
0 1
54ACT
T
A
e
b
55 C to
a
125 C
CGS74CT
T
A
e
b
40 C to
a
85 C
Units
Conditions
Guaranteed Limits
20
20
08
08
44
54
3 70
4 70
01
01
0 50
0 50
g
1 0
20
20
08
08
44
54
3 76
4 76
01
01
0 44
0 44
g
1 0
V
V
V
V
OUT
e
0 1V
or V
CC
b
0 1V
V
OUT
e
0 1V
or V
CC
b
0 1V
I
OUT
e b
50
mA
V
IN
e
V
IL
or V
IH
b
24 mA
I
OH
b
24 mA
I
OUT
e
50
mA
V
IN
e
V
IL
or V
IH
24 mA
I
OL
24 mA
V
I
e
V
CC
GND
V
I
e
V
CC
b
2 1V
V
OLD
e
1 65V Max
V
OHD
e
3 85V Min
V
IN
e
V
CC
or GND
V
V
V
mA
mA
mA
mA
16
50
b
50
15
75
b
75
55
80
160 0
80 0
mA
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AC Electrical Characteristics
Over recommended operating conditions unless specified otherwise
CGS74C
54AC
T
A
e b
55 C
to
a
125 C
C
L
e
50 pF
Min
30
25
Max
11 0
82
CGS74C
T
A
e b
40 C
to
a
85 C
C
L
e
50 pF
Min
30
29
30
33
30
35
15
10
15
10
15
Typ
Max
12 5
81
14 0
86
15 0
95
600
ps
500
600
ps
500
ns
ns
ns
Units
Symbol
Parameter
V
CC
Range
(V)
(Note 6)
33
50
33
50
33
50
33
50
33
50
T
A
e a
25 C
C
L
e
50 pF
Min
Typ
65
50
70
55
80
65
03
02
03
02
Max
11 0
78
13 0
78
14 0
85
t
PLH
t
PHL
t
PLH
t
PHL
t
PLH
t
PHL
t
OSHL
Propagation Delay
CLK to O
n
(’2525)
Propagation Delay
CLKn to O
n
(’2526)
Propagation Delay
SEL to O
n
(’2526)
Maximum Skew
Common Edge
Output-to-Output (Note 7)
Variation
Maximum Skew
Common Edge
Output-to-Output (Note 7)
Variation
Maximum Skew
Opposite Edge
Output-to-Output (Note 7)
Variation
Maximum Skew
Part-to-Part
Variation (Note 8)
’C2525
’CT2525
’C2526
’CT2526
30
32
30
36
30
40
t
OSLH
t
OST
50
04
10
10
10
ns
t
PV
50
50
50
35
50
30
40
ns
ns
t
rise
t
fall
t
rise
t
fall
Maximum
Rise Fall Time
(20% to 80% V
CC
)
Maximum
Rise Fall Time
(0 8V 2 0V and 2 0V 0 8V)
40
3 75
ns
09
11
ns
AC Electrical Characteristics
Over recommended operating conditions unless specified otherwise
CGS74CT
Symbol
Parameter
V
CC
Range
(V)
(Note 6)
Min
t
PLH
t
PHL
t
PLH
t
PHL
Propagation Delay
CLK to O
n
(’2525)
Propagation Delay
CLKn to O
n
(’2526)
50
50
46
58
T
A
e a
25 C
C
L
e
50 pF
Typ
65
85
Max
90
11 1
54ACT
T
A
e b
55 C
to
a
125 C
C
L
e
50 pF
Min
Max
CGS74CT
T
A
e b
40 C
to
a
85 C
C
L
e
50 pF
Min
40
51
Max
10 1
12 4
ns
ns
Units
5
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