NSC CGS74B2525

CGS74B2525
1-to-8 Minimum Skew Clock Driver
General Description
Features
This minimum skew clock driver is designed for Clock Generation and Support (CGS) applications operating well
above 20 MHz (33 MHz, 50 MHz). The device guarantees
minimum output skew across the outputs of a given device
and also from device-to-device. Skew parameters are also
provided as a means to measure duty cycle requirements as
those found in high speed clocking systems. The ’B2525 is
a minimum skew clock driver with one input driving eight
outputs specifically designed for signal generation and clock
distribution applications.
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Logic Symbol
Clock Generation and Support (CGS) DeviceÐIdeal for
high frequency signal generation or clock distribution
applications
CGS74B version features National’s Advanced Bipolar
FASTÉ LSI process
1-to-8 low skew clock distribution
600 ps pin-to-pin output skew
Specifications for device-to-device variation of propagation delay
Specification for transition skew to meet duty cycle
requirements
Center pin VCC and GND configuration to minimize high
speed switching noise
Current sourcing 48 mA and current sinking of 64 mA
Low dynamic power consumption above 20 MHz
Guaranteed 4 kV ESD protection
Connection Diagram
Pin Assignment
for DIP and SOIC
TL/F/10907 – 1
TL/F/10907 – 2
FASTÉ and TRI-STATEÉ are registered trademarks of National Semiconductor Corporation.
C1995 National Semiconductor Corporation
TL/F/10907
RRD-B30M115/Printed in U. S. A.
CGS74B2525 1-to-8 Minimum Skew Clock Driver
September 1995
Functional Description
Truth Table
Pin Description
Pin Names
CLK
O0 – O7
Description
Inputs
Outputs
Clock Input
Outputs
CLK
O0 –O7
L
H
L
H
TL/F/10907 – 5
2
Absolute Maximum Ratings (Note 1)
Recommended Operating
Conditions
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales
Office/Distributors for availability and specifications.
Supply Voltage (VCC)
Input Voltage (VI)
Operating Free Air Temperature
Storage Temperature Range
Junction Temperature (iJA)
Plastic (N) Package
JEDEC SOIC (M) Package
Supply Voltage (VCC)
104
120
4.5V to 5.5V
Input Rise and Fall Times
(0.8V to 2.0V)
Free Air Operating Temperature (TA)
7.0V
7.0V
0§ C to a 70§ C
b 65§ C to a 150§ C
9.6 ns max
0§ C to a 70§ C
Note 1: The Absolute Maximum Ratings are those values beyond which the
safety of the device cannot be guaranteed. The device should not be operated at these limits. The parametric values defined in the DC and AC Electrical
Characteristics tables are not guaranteed at the absolute maximum ratings.
The Recommended Operating Conditions will define the conditions for actual device operation.
§ C/W
§ C/W
DC Electrical Characteristics
over recommended operating conditions unless specified otherwise. All typical values are measured at VCC e 5V, TA e 25§ C.
Symbol
Parameter
Conditions
Min
Typ
VCC e 4.5V, II e b18 mA
Max
Units
b 1.2
V
VIK
Input Clamp Voltage
VIH
Minimum Input
High Level Voltage
VIL
Maximum Input
Low Level Voltage
VOH
High Level Output
Voltage
IOH e b3 mA, VCC e 4.5V
2.4
IOH e b48 mA, VCC e 4.5V
2.0
VOL
Low Level Output
Voltage
VCC e 4.5V, IOL e 64 mA
II
Input Current @
Max Input Voltage
VCC e 5.5V, VIH e 7V
IIH
High Level Input Current
VCC e 5.5V, VIH e 2.7V
20
mA
IIL
Low Level Input Current
VCC e 5.5V, VIH e 0.4V
b 0.5
mA
IO
Output Drive Current
VCC e 5.5V, VO e 2.25V
ICC
Supply Current
VCC e 5.5V
CIN
Input Capacitance
VCC e 5V
2.0
V
0.8
V
0.35
b 50
0.5
V
0.1
mA
b 150
mA
Outputs High
8
15
mA
Outputs Low
32
42
mA
5
3
V
pF
AC Electrical Characteristics
Over recommended operating conditions unless specified otherwise.
CGS74B2525
Symbol
tPLH
tPHL
VCC e 4.5V to 5.5V
RL e 500X, CL e 50 pF
Parameter
Propagation Delay
CLK to On
Units
Min
Typ
Max
2
2
3.0
3.0
4.8
4.8
ns
Extended AC Electrical Characteristics
Over recommended operating conditions unless specified otherwise.
CGS74B2525
Symbol
VCC e 4.5V to 5.5V
RL e 500X, CL e 50 pF,
TA e 0§ C to 70§ C
Parameter
Min
Typ
Units
Max
fmax
Maximum Operating Frequency
tOSHL
Maximum Skew Common Edge
Output-to-Output Variation
(Note 2)
150
600
ps
Maximum Skew Common Edge
Output-to-Output Variation
(Note 2)
150
600
ps
Maximum Skew Opposite Edge
Output-to-Output Variation
(Note 2)
0.7
1.5
ns
1.75
ns
1.5
ns
1.6
1.4
ns
ns
tOSLH
tOST
tPV
tPS
trise,
tfall
50
MHz
Maximum Skew
Part-to-Part Variation Skew
(Note 3)
Maximum Skew
Pin (Signal) Transition Variation
(Note 2)
0.6
Maximum Rise/Fall Time
(from 0.8V to 2.0V/2.0V to 0.8V)
Note 2: Output-to-Output Skew is defined as the absolute value of the difference between the actual propagation delay for any outputs within the same packaged
device. The specifications apply to any outputs switching in the same direction either HIGH to LOW (tOSHL) or LOW to HIGH (tOSLH) or in opposite directions both
HL and LH (tOST). Parameters tOST and tPS guaranteed by design. tOSHL and tOSLH are characterized and guaranteed by design @ 1 MHz.
Note 3: Part-to-part skew is defined as the absolute value of the difference between the propagation delay for any outputs from device to device. The parameter is
specified for a given set of conditions (i.e., capacitive load, VCC, temperature, Ý of outputs switching, etc.). Parameter guaranteed by design.
Note 4: Load capacitance includes the test jig.
4
Timing Diagrams
TL/F/10907 – 16
TL/F/10907 – 17
Test Circuit
RL is 500X
CL is 50 pF for all prop delays and skew measurements
TL/F/10907 – 18
5
Ordering Information
The device number is used to form part of a simplified purchasing code where the package type and temperature range are
defined as follows:
TL/F/10907 – 19
6
Physical Dimensions inches (millimeters)
14-Lead Small Outline Integrated Circuit
NS Package Number M14A
7
CGS74B2525 1-to-8 Minimum Skew Clock Driver
Physical Dimensions inches (millimeters) (Continued)
14-Lead Plastic Dual-In-Line Package
NS Package Number N14A
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