September 2005
rev 1.6
3.3V Zero Delay Buffer
General Features
15MHz to 133MHz operating range, compatible
with CPU and PCI bus frequencies.
Zero input - output propagation delay.
Multiple low-skew outputs.
Output-output skew less than 250pS.
Device-device skew less than 700pS.
One input drives 9 outputs, grouped as
4 + 4 + 1(ASM5P2309A).
One input drives 5 outputs (ASM5P2305A).
Less than 200 pS cycle-to-cycle jitter is compatible
with Pentium
®
based systems.
Test Mode to bypass PLL (ASM5P2309A only,
Refer Select Input Decoding Table).
Available in 16pin 150-mil SOIC, 4.4 mm TSSOP
(ASM5P2309A), and in 8pin 150-mil SOIC
package (ASM5P2305A).
3.3V operation, advanced 0.35µ CMOS
technology.
ASM5P2309A
ASM5P2305A
133MHz frequencies, and has higher drive than the -1
devices. All parts have on-chip PLLs that lock to an input
clock on the REF pin. The PLL feedback is on-chip and is
obtained from the CLKOUT pad.
The ASM5P2309A has two banks of four outputs each,
which can be controlled by the Select inputs as shown in
the Select Input Decoding Table. The select input also
allows the input clock to be directly applied to the outputs
for chip and system testing purposes.
Multiple ASM5P2309A and ASM5P2305A 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 700pS.
All outputs have less than 200pS of cycle-to-cycle jitter.
The input and output propagation delay is guaranteed to be
less than 350pS, and the output to output skew is
guaranteed to be less than 250pS.
The ASM5P2309A and the ASM5P2305A are available in
two different configurations, as shown in the ordering
information table. The ASM5P2305A-1/ ASM5P2309A-1 is
the base part. The ASM5P2305A-1H/ ASM5P2309A-1H is
the high drive version of the -1 and its rise and fall times
are much faster than -1 part.
Functional Description
ASM5P2309A is a versatile, 3.3V zero-delay buffer
designed to distribute high-speed clocks. It accepts one
reference input and drives out nine low-skew clocks. It is
available in a 16-pin package. The ASM5P2305A is the
eight-pin version of the ASM5P2309A. It accepts one
reference input and drives out five low-skew clocks.
The -1H version of the ASM5P23XXA operates at up to
Block Diagram
PLL
PLL
CLKOUT
CLK1
CLK2
CLK3
S2
S1
REF
MUX
CLKOUT
CLKA1
CLKA2
CLKA3
CLKA4
Select Input
Decoding
CLKB1
CLKB2
CLKB3
REF
ASM5P2305A
CLK4
ASM5P2309A
CLKB4
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.
September 2005
rev 1.6
Select Input Decoding for ASM5P2309A
S2
0
0
1
1
Notes:
ASM5P2309A
ASM5P2305A
S1
0
1
0
1
Clock A1 - A4
Three-state
Driven
Driven
Driven
Clock B1 - B4
Three-state
Three-state
Driven
Driven
CLKOUT
1
Driven
Driven
Driven
Driven
Output Source
PLL
PLL
Reference
PLL
PLL
Shut-Down
N
N
Y
N
1. This output is driven and has an internal feedback for the PLL. The load on this output can be adjusted to change the skew between the reference and the
output.
Zero Delay and Skew Control
All outputs should be uniformly loaded to achieve Zero
Delay between input and output. Since the CLKOUT pin is
the internal feedback to the PLL, its relative loading can
adjust the input-output delay.
For applications requiring zero input-output delay, all
outputs, including CLKOUT, must be equally loaded. Even
if CLKOUT is not used, it must have a capacitive load equal
to that on other outputs, for obtaining zero-input-output
delay.
3.3V Zero Delay Buffer
Notice: The information in this document is subject to change without notice.
2 of 20
September 2005
rev 1.6
Pin Configuration
REF 1
CLKA1
CLKA2
V
DD
GND
2
3
4
5
16 CLKOUT
15 CLKA4
14 CLKA3
13 V
DD
12 GND
11 CLKB4
10 CLKB3
9
S1
ASM5P2309A
ASM5P2305A
ASM5P2309A
CLKB1 6
CLKB2 7
S2
8
REF
CLK2
CLK1
GND
1
2
8
7
CLKOUT
CLK4
V
DD
CLK3
ASM5P2305A
3
4
6
5
Pin Description for ASM5P2309A
Pin #
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Pin Name
REF
2
CLKA1
3
CLKA2
3
V
DD
GND
CLKB1
3
CLKB2
S2
4
S1
4
CLKB3
GND
V
DD
CLKA3
3
CLKA4
3
CLKOUT
3
3
3
Description
Input reference frequency, 5V tolerant input
Buffered clock output, bank A
Buffered clock output, bank A
3.3V supply
Ground
Buffered clock output, bank B
Buffered clock output, bank B
Select input, bit 2
Select input, bit 1
Buffered clock output, bank B
Buffered clock output, bank B
Ground
3.3V supply
Buffered clock output, bank A
Buffered clock output, bank A
Buffered output, internal feedback on this pin
CLKB4
3
3.3V Zero Delay Buffer
Notice: The information in this document is subject to change without notice.
3 of 20
September 2005
rev 1.6
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
(As per JEDEC STD22- A114-B)
ASM5P2309A
ASM5P2305A
Min
-0.5
-0.5
-0.5
-65
Max
+7.0
V
DD
+ 0.5
7
+150
260
150
2000
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 ASM5P2305A and ASM5P2309A - Commercial Temperature Devices
Parameter
V
DD
T
A
C
L
C
L
C
IN
Supply Voltage
Operating Temperature (Ambient Temperature)
Load Capacitance, below 100MHz
Load Capacitance, from 100MHz to 133MHz
Input Capacitance
Description
Min
3.0
0
Max
3.6
70
30
10
7
Unit
V
°C
pF
pF
pF
3.3V Zero Delay Buffer
Notice: The information in this document is subject to change without notice.
5 of 20
Embedded System
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