W132
Spread Aware™, Ten/Eleven Output Zero Delay Buffer
Features
• Spread Aware™—designed to work with SSFTG refer-
ence signals
• Well suited to both 100- and 133-MHz designs
• Ten (-09B) or Eleven (-10B) LVCMOS/LVTTL outputs
• Single output enable pin for -10 version, dual pins on
-09 devices allow shutting down a portion of the out-
puts.
• 3.3V power supply
• On board 25Ω damping resistors
• Available in 24-pin TSSOP package
Key Specifications
Operating Voltage: ................................................ 3.3V±10%
Operating Range: ........................25 MHz < f
OUT
< 140 MHz
Cycle-to-Cycle Jitter: ................................................<150 ps
Output to Output Skew: ............................................<100 ps
Phase Error Jitter: .....................................................<125 ps
Block Diagram
FBIN
CLK
Pin Configurations
PLL
FBOUT
Q0
Q1
Q2
AGND
VDD
Q0
Q1
Q2
GND
GND
Q3
Q4
VDD
OE
FBOUT
1
2
3
4
5
6
7
8
9
10
11
12
24
23
22
21
20
19
18
17
16
15
14
13
CLK
AVDD
VDD
Q9
Q8
GND
GND
Q7
Q6
Q5
VDD
FBIN
W132-10B
OE0:4
Q3
OE
Q4
Q5
OE5:8
Q6
Q7
Q8
Q9
configuration of these blocks dependent upon specific option being used
AGND
VDD
Q0
Q1
Q2
GND
GND
Q3
Q4
VDD
OE0:4
FBOUT
1
2
3
4
5
6
7
8
9
10
11
12
24
23
22
21
20
19
18
17
16
15
14
13
CLK
AVDD
VDD
Q8
Q7
GND
GND
Q6
Q5
VDD
OE5:8
FBIN
W132-09B
Spread Aware is a trademark of Cypress Semiconductor Corporation.
Cypress Semiconductor Corporation
Document #: 38-07216 Rev. *A
•
3901 North First Street
•
San Jose
•
CA 95134 • 408-943-2600
Revised December 22, 2002
W132
Pin Definitions
Pin
Name
CLK
FBIN
Pin No.
(-09B)
24
13
Pin No.
(-10B)
24
13
Pin
Type
I
I
Pin Description
Reference Input:
Output signals Q0:9 will be synchronized to this signal.
Feedback Input:
This input must be fed by one of the outputs (typically FBOUT)
to ensure proper functionality. If the trace between FBIN and FBOUT is equal in
length to the traces between the outputs and the signal destinations, then the
signals received at the destinations will be synchronized to the CLK signal input.
Integrated Series Resistor Outputs:
The frequency and phase of the signals
provided by these pins will be equal to the reference signal if properly laid out.
Each output has a 25Ω series damping resistor integrated.
Integrated Series Resistor Output:
The frequency and phase of the signal
provided by this pin will be equal to the reference signal if properly laid out. This
output has a 25Ω series damping resistor integrated.
Feedback Output:
This output has a 25Ω series resistor integrated on chip.
Typically it is connected directly to the FBIN input with a trace equal in length to
the traces between outputs Q0:9 and the destination points of these output
signals.
Analog Power Connection:
Connect to 3.3V. Use ferrite beads to help reduce
noise for optimal jitter performance.
Analog Ground Connection:
Connect to common system ground plane.
Power Connections:
Connect to 3.3V. Use ferrite beads to help reduce noise
for optimal jitter performance.
Ground Connections:
Connect to common system ground plane.
Output Enable Input:
Tie to V
DD
(HIGH, 1) for normal operation. when brought
to GND (LOW, 0) all outputs are disabled to a LOW state.
Output Enable Input:
Tie to V
DD
(HIGH, 1) for normal operation. when brought
to GND (LOW, 0) outputs Q0:4 are disabled to a LOW state.
Output Enable Input:
Tie to V
DD
(HIGH, 1) for normal operation. when brought
to GND (LOW, 0) outputs Q5:8 are disabled to a LOW state.
on the DIMM. The W132 takes in the signal from the mother-
board and buffers out clock signals with enough drive to sup-
port all the DIMM board clocking needs. The W132 is also
designed to meet the needs of new PC133 SDRAM designs,
operating to 133 MHz.
The W132 was specifically designed to accept SSFTG signals
currently being used in motherboard designs to reduce EMI.
Zero delay buffers which are not designed to pass this feature
through may cause skewing failures.
Output enable pins allow for shutdown of output when they are
not being used. This reduces EMI and power consumption.
Q0:8
3, 4, 5, 8,
9, 16, 17,
20, 21
n/a
3, 4, 5, 8,
9, 15, 16,
17, 20
21
O
Q9
O
FBOUT
12
12
O
AVDD
AGND
VDD
GND
OE
OE0:4
OE5:8
23
1
2, 10, 15,
22
6, 7, 18,
19
n/a
11
14
23
1
2, 10, 14,
22
6, 7, 18,
19
11
n/a
n/a
P
G
P
G
I
I
I
Overview
The W132 is a PLL-based clock driver designed for use in dual
inline memory modules. The clock driver has output frequen-
cies of up to 133 MHz and output to output skews of less than
250 ps. The W132 provides minimum cycle-to-cycle and long
term jitter, which is of significant importance to meet the tight
input-to-input skew budget in DIMM applications.
The current generation of 256 and 512 megabyte memory
modules needs to support 100-MHz clocking speeds. Espe-
cially for cards configured in 16x4 or 8x8 format, the clock
signal provided from the motherboard is generally not strong
enough to meet all the requirements of the memory and logic
Document #: 38-07216 Rev. *A
Page 2 of 6
W132
1
AGND
VDD
Q0
Q1
Q2
GND
GND
Q3
Q4
VDD
OE
FBOUT
GND
AVDD
VDD
Q9
Q8
GND
GND
Q7
Q6
Q5
VDD
FBIN
24
23
22
21
20
19
18
17
16
15
14
13
VDD
0.1µF
2
3
4
5
6
7
8
9
0.1µF
10µF
VDD
FB
3.3V
0.1µF
10µF
FB
VDD
0.1µF
10
11
12
0.1µF
VDD
Figure 1. Schematic
Spread Aware
Many systems being designed now utilize a technology called
Spread Spectrum Frequency Timing Generation. Cypress has
been one of the pioneers of SSFTG development, and we de-
signed this product so as not to filter off the Spread Spectrum
feature of the Reference input, assuming it exists. When a
zero delay buffer is not designed to pass the SS feature
through, the result is a significant amount of tracking skew
which may cause problems in systems requiring synchroniza-
tion.
For more details on Spread Spectrum timing technology,
please see the Cypress application note titled, “EMI Suppres-
sion Techniques with Spread Spectrum Frequency Timing
Generator (SSFTG) ICs.”
If it is desirable to either add a little delay, or slightly precede
the input signal, this may also be affected by either making the
trace to the FBIN pin a little shorter or a little longer than the
traces to the devices being clocked.
Inserting Other Devices in Feedback Path
Another nice feature available due to the external feedback is
the ability to synchronize signals up to the signal coming from
some other device. This implementation can be applied to any
device (ASIC, multiple output clock buffer/driver, etc.) which is
put into the feedback path.
Referring to
Figure 2,
if the traces between the ASIC/buffer
and the destination of the clock signal(s) (A) are equal in length
to the trace between the buffer and the FBIN pin, the signals
at the destination(s) device will be driven high at the same time
the Reference clock provided to the ZDB goes high. Synchro-
nizing the other outputs of the ZDB to the outputs form the
ASIC/Buffer is more complex however, as any propagation de-
lay in the ASIC/Buffer must be accounted for.
Reference
Signal
Feedback
Input
How to Implement Zero Delay
Typically, zero delay buffers (ZDBs) are used because a de-
signer wants to provide multiple copies of a clock signal in
phase with each other. The whole concept behind ZDBs is that
the signals at the destination chips are all going HIGH at the
same time as the input to the ZDB. In order to achieve this,
layout must compensate for trace length between the ZDB and
the target devices. The method of compensation is described
below.
External feedback is the trait that allows for this compensation.
The PLL on the ZDB will cause the feedback signal to be in
phase with the reference signal. When laying out the board,
match the trace lengths between the output being used for
feed back and the FBIN input to the PLL.
Zero
Delay
Buffer
ASIC/
Buffer
A
Figure 2. 6 Output Buffer in the Feedback Path
Document #: 38-07216 Rev. *A
Page 3 of 6
W132
Absolute Maximum Ratings
[1]
Stresses greater than those listed in this table may cause per-
manent damage to the device. These represent a stress rating
only. Operation of the device at these or any other conditions
.
above those specified in the operating sections of this specifi-
cation is not implied. Maximum conditions for extended peri-
ods may affect reliability.
Rating
–0.5 to +7.0
–65 to +150
0 to +70
–55 to +125
0.5
Unit
V
°C
°C
°C
W
Parameter
V
DD
, V
IN
T
STG
T
A
T
B
P
D
Description
Voltage on any pin with respect to GND
Storage Temperature
Operating Temperature
Ambient Temperature under Bias
Power Dissipation
DC Electrical Characteristics
:
T
A
=0°C to 70°C, V
DD
= 3.3V ±10%
Parameter
I
DD
V
IL
V
IH
V
OL
V
OH
I
IL
I
IH
Description
Supply Current
Input Low Voltage
Input High Voltage
Output Low Voltage
Output High Voltage
Input Low Current
Input High Current
I
OL
= 12 mA
I
OH
= –12 mA
V
IN
= 0V
V
IN
= V
DD
2.1
50
50
2.0
0.8
Test Condition
Unloaded, 100 MHz
Min
Typ
Max
200
0.8
Unit
mA
V
V
V
V
µA
µA
AC Electrical Characteristics:
T
A
= 0°C to +70°C, V
DD
= 3.3V ±10%
Parameter
f
OUT
t
R
t
F
t
ICLKR
t
ICLKF
t
PEJ
t
SK
t
D
t
LOCK
t
JC
Description
Output Frequency
Output Rise Time
Output Fall Time
Input Clock Rise Time
[2]
Input Clock Fall Time
[2]
CLK to FBIN Skew Variation
[3, 4]
Output to Output Skew
Duty Cycle
PLL Lock Time
Jitter, Cycle-to-Cycle
Measured at V
DD
/2
All outputs loaded equally
30-pF load
Power supply stable
–350
–100
43
0
0
50
Test Condition
30-pF load
[5]
0.8V to 2.0V, 30-pF load
2.0V to 0.8V, 30-pF load
Min
25
Typ
Max
140
2.1
2.5
4.5
4.5
350
100
58
1.0
150
Unit
MHz
ns
ns
ns
ns
ps
ps
%
ms
ps
Notes:
1. Multiple Supplies: The voltage on any input or I/O pin cannot exceed the power pin during power-up. Power supply sequencing is NOT required.
2. Longer input rise and fall time will degrade skew and jitter performance.
3. Skew is measured at V
DD
/2 on rising edges.
4. Duty cycle is measured at V
DD
/2.
5. Production tests are run at 133 MHz.
Ordering Information
Ordering Code
W132
Option
-09B, -10B
Package Type
X = 24-pin TSSOP
Document #: 38-07216 Rev. *A
Page 4 of 6
W132
Package Diagram
24-Pin Thin Shrink Small Outline Package (TSSOP)
Document #: 38-07216 Rev. *A
Page 5 of 6
© Cypress Semiconductor Corporation, 2001. The information contained herein is subject to change without notice. Cypress Semiconductor Corporation assumes no responsibility for the use
of any circuitry other than circuitry embodied in a Cypress Semiconductor product. Nor does it convey or imply any license under patent or other rights. Cypress Semiconductor does not authorize
its products for use as critical components in life-support systems where a malfunction or failure may reasonably be expected to result in significant injury to the user. The inclusion of Cypress
Semiconductor products in life-support systems application implies that the manufacturer assumes all risk of such use and in doing so indemnifies Cypress Semiconductor against all charges.
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