August 2004
rev 2.0
3.3 V
‘SpreadTrak’ Zero Delay Buffer
Features
Zero input - output propagation delay,
adjustable by capacitive load on FBK input.
Multiple configurations -
Refer “ASM5P23S04A
Configurations Table”.
Input frequency range: 10MHz to 133MHz
Multiple low-skew outputs.
Output-output skew less than 200 ps.
Device-device skew less than 500 ps.
Two banks of four outputs.
Less than 200 ps cycle-to-cycle jitter
Available in space saving, 8-pin 150-mil SOIC
packages.
3.3V operation.
Advanced 0.35µ CMOS technology.
Industrial temperature available.
‘SpreadTrak’
Functional Description
ASM5P23S04A is a versatile, 3.3V zero-delay buffer
designed
to
distribute
high-speed
clocks
in
PC,
workstation, datacom, telecom and other high-performance
applications. It is available in a 8-pin package. The part has
an on-chip PLL which locks to an input clock presented on
the REF pin. The PLL feedback is required to be driven to
ASMP5P23S04A
FBK pin, and can be obtained from one of the outputs. The
input-to-output propagation delay is guaranteed to be less
than 250ps, and the output-to-output skew is guaranteed to
be less than 200ps.
The ASM5P23S04A has two banks of two outputs each.
Multiple ASM5P23S04A devices can accept the same input
clock and distribute it. In this case the skew between the
outputs of the two devices is guaranteed to be less than
500ps.
The
ASM5P23S04A
(Refer
is
available
in
two
different
configurations
“ASM5P23S04A
Configurations
Table). The ASM5P23S04A-1 is the base part, where the
output frequencies equal the reference if there is no
counter in the feedback path. The ASM5P23S04A-1H is
the high-drive version of the -1 and the rise and fall times
on this device are much faster.
The ASM5P23S04A-2 allows the user to obtain Ref, 1/2 X
and 2X frequencies on each output bank. The exact
configuration and output frequencies depend on which
output drives the feedback pin. The ASM5P23S04A-5H is a
high-drive version with REF/2 on both banks
Block Diagram
FBK
CLKA1
REF
PLL
CLKA2
/2
Extra Divider (-2)
CLKB1
CLKB2
Alliance Semiconductor
2575, Augustine Drive
Santa Clara, CA
Tel: 408.855.4900
Fax: 408.855.4999
www.alsc.com
Notice: The information in this document is subject to change without notice.
``
August 2004
rev 2.0
ASM5P23S04A Configurations
Device
ASM5P23S04A-1
ASM5P23S04A-1H
ASM5P23S04A-2
ASM5P23S04A-2
ASM5P23S04A-5H
‘SpreadTrak’
Many systems being designed now utilize a
technology called Spread Frequency Timing
Generation. ASM3P23S04A is designed so as not
to filter off the Spread Spectrum feature of the
Reference input, assuming it exists. When a zero
Zero Delay and Skew Control
For applications requiring zero input-output delay, all outputs must be equally loaded.
1500
ASM5P23S04A
Feedback From
Bank A or Bank B
Bank A or Bank B
Bank A
Bank B
Bank A or Bank B
Bank A Frequency
Reference
Reference
Reference
2 X Reference
Reference /2
Bank B Frequency
Reference
Reference
Reference /2
Reference
Reference /2
delay buffer is not designed to pass the Spread
Spectrum feature through, the result is a significant
amount of tracking skew which may cause
problems in the systems requiring synchronization.
1000
REF-Input to CLKA/CLKB Delay (ps)
500
0
-30
-500
-25
-20
-15
-10
-5
0
5
10
15
20
25
30
-1000
-1500
Output Load Difference: FBK Load - CLKA/CLKB Load (pF)
REF Input to CLKA/CLKB Delay Vs Difference in Loading between FBK pin and CLKA/CLKB pins
3.3
‘SpreadTrak’ Zero Delay Buffer
Notice: The information in this document is subject to change without notice.
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August 2004
rev 2.0
To close the feedback loop of the ASM5P23S04A,
the FBK pin can be driven from any of the four
available output pins. The output driving the FBK pin
will be driving a total load of 7 pF plus any additional
load that it drives. The relative loading of this output
(with respect to the remaining outputs) can adjust the
input output delay. This is shown in the above graph.
Pin Configuration
REF
CLKA1
CLKA2
GND
1
2
3
4
8
FBK
V
DD
CLKB2
ASM5P23S04A
For applications requiring zero input-output delay, all
outputs including the one providing feedback should
be equally loaded. If input-output delay adjustments
are required, use the above graph to calculate
loading differences between the feedback output and
remaining outputs. For zero output-output skew, be
sure to load outputs equally.
ASM5P23S04A
7
6
5
CLKB1
Pin Description for ASM5P23S04A
Pin #
1
2
3
4
5
6
7
8
Pin Name
REF
1
CLKA1
2
CLKA2
GND
CLKB1
2
CLKB2
2
V
DD
FBK
2
Description
Input reference frequency, 5V tolerant input
Buffered clock output, bank A
Buffered clock output, bank A
Ground
Buffered clock output, bank B
Buffered clock output, bank B
3.3V supply
PLL feedback input
Notes:
1. Weak pull-down.
2. Weak pull-down on all outputs.
3.3
‘SpreadTrak’ Zero Delay Buffer
Notice: The information in this document is subject to change without notice.
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August 2004
rev 2.0
Absolute Maximum Ratings
Parameter
Supply Voltage to Ground Potential
DC Input Voltage (Except REF)
DC Input Voltage (REF)
Storage Temperature
Max. Soldering Temperature (10 sec)
Junction Temperature
Static Discharge Voltage
(per MIL-STD-883, Method 3015)
Min
-0.5
-0.5
-0.5
-65
Max
+7.0
V
DD
+ 0.5
7
+150
260
150
>2000
ASM5P23S04A
Unit
V
V
V
°
C
°
C
°
C
V
Note: These are stress ratings only and functional usage is not implied. Exposure to absolute
maximum
ratings for prolonged periods can affect device reliability.
Operating Conditions for ASM5P23S04A Commercial Temperature Devices
Parameter
V
DD
T
A
C
L
C
L
C
IN
Supply Voltage
Description
Min
3.0
0
Max
3.6
70
30
15
7
Unit
V
°
C
Operating Temperature (Ambient Temperature)
Load Capacitance, below 100 MHz
Load Capacitance, from 100 MHz to 133 MHz
Input Capacitance
3
pF
pF
pF
Note: 3. Applies to both Ref Clock and FBK.
3.3
‘SpreadTrak’ Zero Delay Buffer
Notice: The information in this document is subject to change without notice.
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August 2004
rev 2.0
Electrical Characteristics for ASM5P23S04A Commercial Temperature Devices
ASM5P23S04A
Parameter
V
IL
V
IH
I
IL
I
IH
V
OL
Description
Input LOW Voltage
Input HIGH Voltage
Input LOW Current
Input HIGH Current
Output LOW Voltage
4
Test Conditions
Min
Max
0.8
Unit
V
V
2.0
V
IN
= 0V
V
IN
= V
DD
I
OL
= 8mA (-1, -2)
I
OH
= 12mA (-1H, -5H)
I
OL
= -8mA (-1, -2)
I
OH
= -12mA (-1H, -5H)
Unloaded outputs 100MHz REF,
Select inputs at V
DD
or GND
2.4
50.0
100.0
µA
µA
0.4
V
V
OH
Output HIGH Voltage
4
V
TBD
TBD
mA
I
DD
Supply Current
Unloaded outputs, 66MHz REF
(-1, -2)
Unloaded outputs, 33MHz REF
(-1, -2)
TBD
TBD
Note: 4. Parameter is guaranteed by design and characterization. Not 100% tested in production.
5. REF Input Vth = ~ VDD/2
3.3
‘SpreadTrak’ Zero Delay Buffer
Notice: The information in this document is subject to change without notice.
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MCU
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