CYPRESS W234_02

W234
Dual Direct Rambus™ Clock Generator
Features
Overview
• Differential clock source for Direct Rambus™ memory
subsystem for up to 1.6-Gb/s serial data transfer rate
• Provide synchronization flexibility: the Rambus® Channel can optionally be synchronous to an external system or processor clock
• Power managed output allows Rambus Channel clock
to be turned off to minimize power consumption for
mobile applications
• Works with Cypress CY2210-2, CY2210-3, CY2215,
W133, W158, W159, W161, and W167B to support Intel®
architecture platforms
• Low-power CMOS design packaged in a 28-pin, 173-mil
TSSOP package
The Cypress W234 provides dual channel differential clock
signals for a Direct Rambus memory subsystem. It includes
signals to synchronize the Direct Rambus Channel clock to an
external system clock but can also be used in systems that do
not require synchronization of the Rambus clock.
Key Specifications
Supply Voltage: ................................... VDD = 3.3V ± 0.165V
Operating Temperature: ................................... 0°C to +70°C
Input Threshold: .................................................. 1.5V typical
Maximum Input Voltage: .......................................VDD + 0.5V
Maximum Input Frequency: ..................................... 100 MHz
Output Duty Cycle: .................................. 40/60% worst case
Output Type:........................... Rambus signaling level (RSL)
Block Diagram
PCLKM0
SYNCLKN0
REFCLK
MULT0:2
S0:2
Pin Configuration
Phase
Alignment
Output
Logic
VDDIR
1
28
S0
REFCLK
VDD
2
27
S1
3
26
S2
SYNCLKN0
4
25
GND
PCLKM0
5
24
CLK0#
GND
6
23
CLK0
VDD
7
22
VDD
GND
8
21
VDD
SYNCLKN1
9
20
CLK1
PCLKM1
10
19
CLK1#
VDD
11
18
GND
12
13
17
MULT0
16
MULT1
14
15
MULT2
CLK0
CLK0#
PLL
Test
Logic
VDDIPD
STOP#
PWR_DWN#
PCLKM1
SYNCLKN1
Phase
Alignment
Output
Logic
CLK1
CLK1#
PWR_DWN#
STOP#
Direct Rambus is a trademark and Rambus is a registered trademark of Rambus Inc.
Intel is a registered trademark of Intel Corporation.
Cypress Semiconductor Corporation
Document #: 38-07232 Rev. *B
•
3901 North First Street
•
San Jose
•
CA 95134 • 408-943-2600
Revised December 21, 2002
W234
Pin Definitions
Pin
No.
2
Pin
Type
I
PCLKM0:1
5, 10
I
SYNCLKN0:1
4, 9
I
STOP#
13
I
PWR_DWN#
14
I
17, 16, 15
I
Pin Name
REFCLK
MULT 0:2
Pin Description
Reference Clock Input: Reference clock input, normally supplied by a system
frequency synthesizer (Cypress W133).
Phase Detector Input 0:1: The phase difference between this signal and SYNCLKN is used to synchronize the Rambus Channel Clock with the system clock.
Both PCLKM and SYNCLKN are provided by the Gear Ratio Logic in the memory
controller. If the Gear Ratio Logic is not used, this pin would be connected to
ground.
Phase Detector Input 0:1: The phase difference between this signal and PCLKM
is used to synchronize the Rambus Channel Clock with the system clock. Both
PCLKM and SYNCLKN are provided by the Gear Ratio Logic in the memory controller. If the Gear Ratio Logic is not used, this pin would be connected to ground.
Clock Output Enable: When this input is driven to active LOW, it disables the
differential Rambus Channel clocks.
Active LOW Power-Down: When this input is driven to active LOW, it disables
the differential Rambus Channel clocks and places the W234 in Power-Down
mode.
PLL Multiplier Select: These inputs select the PLL prescaler and feedback dividers to determine the multiply ratio for the PLL for the input REFCLK.
MULT0
0
0
0
0
1
1
1
1
CLK0, CLK0#,
CLK1, CLK1#
S0, S1, S2
23, 24, 20,
19
28, 27, 26
VDD
GND
Complementary Output Clock: Differential Rambus Channel clock outputs.
I
Mode Control Input: These inputs control the operating mode of the W234.
1
12
RefV
RefV
3, 7, 11, 21,
22
6, 8, 18, 25
P
Document #: 38-07232 Rev. *B
B
1
2
1
TBD
3
3
1
TBD
A
4
9
6
TBD
8
16
8
TBD
O
S0
0
1
1
0
1
1
0
VDDIR
VDDIPD
MULT2
0
1
0
1
0
1
0
1
MULT1
0
0
1
1
0
0
1
1
G
S1
0
0
1
0
0
1
1
S2
0
0
0
1
1
1
X
MODE
Normal
Bypass
Test
Vendor Test A
Vendor Test B
Reserved
Output Test (OE)
Reference for Refclk: Voltage reference for input reference clock.
Reference for Phase Detector: Voltage reference for phase detector inputs and
STOP#.
Power Connection: Power supply for core logic and output buffers. Connected to
3.3V supply.
Ground Connection: Connect all ground pins to the common system ground
plane.
Page 2 of 14
W234
W234
Refclk
Phase
Align
PLL
Busclk
D
RAC
Pclk/M
RMC
Synclk/N
CY2210-2
CY2210-3
CY2215
W133
W158
W159
W161
W167B
M
N
Pclk
4
DLL
Synclk
Gear
Ratio
Logic
Figure 1. DDLL System Architecture.
DDLL System Architecture and Gear Ratio Logic
Figure 1 shows the Distributed Delay Lock Loop (DDLL) system architecture, including the main system clock source, the
Direct Rambus clock generator (DRCG), and the core logic
that contains the Rambus Access Cell (RAC), the Rambus
Memory Controller (RMC), and the Gear Ratio Logic. (This
diagram abstractly represents the differential clocks as a single Busclk wire.)
The purpose of the DDLL is to frequency-lock and phase-align
the core logic and Rambus clocks (PCLK and SYNCLK) at the
RMC/RAC boundary in order to allow data transfers without
incurring additional latency. In the DDLL architecture, a PLL is
used to generate the desired Busclk frequency, while a distributed loop forms a DLL to align the phase of Pclk and Synclk at
the RMC/RAC boundary.
The main clock source drives the system clock (Pclk) to the
core logic, and also drives the reference clock (Refclk) to the
DRCG. For typical Intel architecture platforms, Refclk will be
half the CPU front side bus frequency. A PLL inside the DRCG
multiplies Refclk to generate the desired frequency for Busclk,
and Busclk is driven through a terminated transmission line
(Rambus Channel). At the mid-point of the channel, the RAC
senses Busclk using its own DLL for clock alignment, followed
by a fixed divide-by-4 that generates Synclk.
Pclk is the clock used in the memory controller (RMC) in the
core logic, and Synclk is the clock used at the core logic inter-
face of the RAC. The DDLL together with the Gear Ratio Logic
enables users to exchange data directly from the Pclk domain
to the Synclk domain without incurring additional latency for
synchronization. In general, Pclk and Synclk can be of different frequencies, so the Gear Ratio Logic must select the appropriate M and N dividers such that the frequencies of Pclk/M
and Synclk/N are equal. In one interesting example,
Pclk=133 MHz, Synclk=100 MHz, and M=4 while N=3, giving
Pclk/M=Synclk/N=33 MHz. This example of the clock waveforms with the Gear Ratio Logic is shown in Figure 2.
The output clocks from the Gear Ratio Logic, Pclk/M, and Synclk/N, are output from the core logic and routed to the DRCG
Phase Detector (φD) inputs. The routing of Pclk/M and Synclk/N must be matched in the core logic as well as on the
board.
After comparing the phase of Pclk/M vs. Synclk/N, the DRCG
Phase Detector (φD) drives a phase aligner that adjusts the
phase of the DRCG output clock, Busclk. Since everything
else in the distributed loop is fixed delay, adjusting Busclk adjusts the phase of Synclk and thus the phase of Synclk/N. In
this manner the distributed loop adjusts the phase of Synclk/N
to match that of Pclk/M, nulling the phase error at the input of
the DRCG Phase Detector (φD). When the clocks are aligned,
data can be exchanged directly from the Pclk domain to the
Synclk domain.
Pclk
Synclk
Pclk/M =
Synclk/N
Figure 2. Gear Ratio Timing Diagram.
Document #: 38-07232 Rev. *B
Page 3 of 14
W234
CY2210-2
CY2210-3
CY2215
W133
Refclk
W158
W159
W161
W167B
W234
Phase
Align
PLL
Busclk
D
RAC
Synclk/N
Pclk/M
RMC
S0/S1/S2 STOP#
M
N
Pclk
4
DLL
Synclk
Gear
Ratio
Logic
Figure 3. DDLL Including Details of DRCG.
Phase Detector Signals
The DRCG Phase Detector (φD) receives two inputs from the
core logic, PCLKM (Pclk/M) and SYNCLKN (Synclk/N). The M
and N dividers in the core logic are chosen so that the frequencies of PCLKM and SYNCLKN are identical. The Phase Detector (φD) detects the phase difference between the two input
clocks, and drives the DRCG Phase Aligner to null the input
phase error through the distributed loop. When the loop is
locked, the input phase error between PCLKM and SYNCLKN
is within the specification tERR,PD given in Table 13 after the
lock time given in the State Transition Section.
The Phase Detector (φD) aligns the rising edge of PCLKM to
the rising edge of SYNCLKN. The duty cycle of the phase detector input clocks will be within the specification DCIN,PD given in Table 12. Because the duty cycles of the two phase detector input clocks will not necessarily be identical, the falling
edges of PCLKM and SYNCLKN may not be aligned when the
rising edges are aligned.
The voltage levels of the PCLKM and SYNCLKN signals are
determined by the controller. The pin VDDIPD is used as the
voltage reference for the phase detector inputs and should be
connected to the output voltage supply of the controller. In
some applications, the DRCG PLL output clock will be used
directly, by bypassing the Phase Aligner. If PCLKM and SYNCLKN are not used, those inputs must be grounded.
Selection Logic
Table 1 shows the logic for selecting the PLL prescaler and
feedback dividers to determine the multiply ratio for the PLL
from the input Refclk. Divider A sets the feedback and divider
B sets the prescaler, so the PLL output clock frequency is set
by: PLLClk=Refclk*A/B.
Document #: 38-07232 Rev. *B
Table 1. PLL Divider Selection
MULT0
MULT1
MULT2
A
B
0
0
0
4
1
0
0
1
9
2
0
1
0
6
1
0
1
1
1
0
0
8
3
1
0
1
16
3
1
1
0
8
1
1
1
1
TBD
TBD
Table 2 shows the logic for enabling the clock outputs, using
the STOP# input signal. When STOP# is HIGH, the DRCG is
in its normal mode, and CLK and CLK# are complementary
outputs following the Phase Aligner output (PAclk). When
STOP# is LOW, the DRCG is in the Clk Stop mode, the output
clock drivers are disabled (set to Hi-Z), and the CLK and CLK#
settle to the DC voltage VX,STOP as given in Table 13. The level
of VX,STOP is set by an external resistor network.
Table 2. Clk Stop Mode Selection
Mode
STOP#
CLK
CLK#
Normal
1
PACLK
PACLK#
Clk Stop
0
VX,STOP
VX,STOP
Table 3 shows the logic for selecting the Bypass and Test
modes. The select bits, S0, S1, and S2 control the selection of
these modes. The Bypass mode brings out the full-speed PLL
output clock, bypassing the Phase Aligner. The Test mode
brings the REFCLK input all the way to the output, bypassing
both the PLL and the Phase Aligner. In the Output Test mode
(OE), both the CLK and CLK# outputs are put into a highimpedance state (Hi-Z). This can be used for component testing and for board-level testing.
Page 4 of 14
W234
Normal
0
0
0
Gnd
PAClk
PAClk#
and the corresponding M and N dividers in the gear ratio logic.
The column Ratio gives the Gear Ratio as defined Pclk/Synclk
(same as M and N). The column [email protected] gives the divided down
frequency (in MHz) at the Phase Detector (φD), where
[email protected] = PCLK/M = SYNCLK/N.
Bypass
1
0
0
PLLClk
PLLClk
PLLClk#
State Transitions
Test
1
1
0
RefClk
RefClk
RefClk#
Vendor Test
A
0
0
1
-
-
-
The clock source has three fundamental operating states.
Figure 4 shows the state diagram with each transition labelled
A through H. Note that the clock source output may NOT be
glitch-free during state transitions.
Vendor Test
B
1
0
1
-
-
-
Reserved
1
1
1
-
-
-
Output Test
(OE)
0
1
X
-
Hi-Z
RefClk#
Table 3. Bypass and Test Mode Selection
Mode
S0 S1 S2
By Pclk
(int.)
CLK
CLK#
Upon powering up the device, the device can enter any state,
depending on the settings of the control signals, PWR_DWN#
and STOP#.
In Power-Down mode, the clock source is powered down with
the control signal, PWR_DWN#, equal to 0. The control signals S0, S1 and S2 must be stable before power is applied to
the device, and can only be changed in Power-Down mode
(PWR_DWN#=0). The reference inputs, VDDIR and VDDIPD,
may remain on or may be grounded during the Power-Down
mode.
Table 4 shows the logic for selecting the Power-Down mode,
using the PWR_DWN# input signal. PWR_DWN# is active
LOW (enabled when 0). When PWR_DWN# is disabled, the
DRCG is in its normal mode. When PWR_DWN# is enabled,
the DRCG is put into a powered-off state, and the CLK and
CLK# outputs are three-stated.
The control signals MULT0, MULT1, and MULT2 can be used
in two ways. If they are changed during Power-Down mode,
then the Power-Down transition timings determine the settling
time of the DRCG. However, the MULT0, MULT1, and MULT2
control signals can also be changed during Normal mode.
When the MULT control signals are “hot swapped” in this manner, the MULT transition timings determine the settling time of
the DRCG.
Table 4. PWR_DWN# Mode Selection
Mode
PWR_DWN#
CLK
CLK#
Normal
1
PAClk
PAClk#
Power-Down
0
GND
GND
Table of Frequencies and Gear Ratios
Table 5 shows several supported Pclk and Busclk frequencies,
the corresponding A and B dividers required in the DRCG PLL,
Table 5. Frequencies, Dividers, and Gear Ratios
Pclk
Refclk
Busclk
Synclk
A
B
M
N
Ratio
[email protected]
67
33
267
67
8
1
2
2
1.0
33
100
50
300
75
6
1
8
6
1.33
12.5
100
50
400
100
8
1
4
4
1.0
25
133
67
267
67
4
1
4
2
2.0
33
133
67
400
100
6
1
8
6
1.33
16.7
Document #: 38-07232 Rev. *B
Page 5 of 14
W234
VDD Turn-On
G
VDD Turn-On
M
J
L
Test
Normal
N
F
B
K
A
VDD Turn-On
E
VDD Turn-On
D
Power-Down
Clk Stop
C
H
Figure 4. Clock Source State Diagram.
In Clk Stop mode, the clock source is on, but the output is
disabled (STOP# asserted). The VDDIPD reference input may
remain on or may be grounded during the Clk Stop mode. The
VDDIR reference input must remain on during the Clk Stop
mode.
In Normal mode, the clock source is on, and the output is enabled.
Table 6 lists the control signals for each state.
Figure 5 shows the timing diagrams for the various transitions
between states, and Table 7 specifies the latencies of each
state transition. Note that these transition latencies assume
the following:
• REFCLK input has settled and meets specification shown
in Table 12.
• MULT0, MULT1, MULT2, S0, S1, and S2 control signals
are stable.
Table 6. Control Signals for Clock Source States
State
PWR_DWN# STOP#
Clock
Source
Output
Buffer
Power-Down
0
X
OFF
Ground
Clk Stop
1
0
ON
Disabled
Normal
1
1
ON
Enabled
Document #: 38-07232 Rev. *B
Page 6 of 14
W234
Timing Diagrams
Power-Down Exit and Entry
PWR_DWN#
tPOWERDN
tPOWERUP
CLK0/CLK0#
CLK1/CLK1#
Output Enable Control
tON
tSTOP
tCLKON
STOP#
tCLKOFF
tCLKSETL
CLK0/CLK0#
CLK1/CLK1#
output clock clock enabled
not specified and glitch free
glitches may
occur.
clock output settled within
50 ps of the phase before
disabled
Figure 5. State Transition Timing Diagrams.
MULT0 and/or MULT1 and/or MULT2
tMULT
CLK0/CLK0#
CLK1/CLK1#
Figure 6. Multiply Transition Timing.
Document #: 38-07232 Rev. *B
Page 7 of 14
W234
Table 7. State Transition Latency Specifications
Transition Latency
Transition
From
To
Symbol
Max.
Description
A
Power-Down
Normal
tPOWERUP
3 ms
Time from PWR_DWN# to rising edge CLK/CLK#
output settled (excluding tDISTLOCK)
C
Power-Down
Clk Stop
tPOWERUP
3 ms
Time from PWR_DWN# rising edge until the internal PLL and clock has turned ON and settled.
K
Power-Down
Test
tPOWERUP
3 ms
Time from PWR_DWN# rising edge to CLK/CLK#
output settled (excluding tDISTLOCK).
G
VDD ON
Normal
tPOWERUP
3 ms
Time from VDD is applied and settled until
CLK/CLK# output settled (excluding tDISTLOCK).
H
VDD ON
Clk Stop
tPOWERUP
3 ms
Time from VDD is applied and settled until
internal PLL and clock has turned ON and settled.
M
VDD ON
Test
tPOWERUP
3 ms
Time from VDD is applied and settled until
internal PLL and clock has turned ON and settled.
J
Normal
Normal
tMULT
1 ms
Time from when MULT0, MULT1, or MULT2
changed until CLK/CLK# output resettled (excluding tDISTLOCK).
E
Clk Stop
Normal
tCLKON
10 ns
Time from STOP# rising edge until CLK/CLK#
provides glitch-free clock edges.
E
Clk Stop
Normal
tCLKSETL
F
Normal
Clk Stop
tCLKOFF
5 ns
Time from STOP# falling edge to CLK/CLK# output disabled.
L
Test
Normal
tCTL
3 ms
Time from when S0, S1, or S2 is changed until
CLK/CLK# output has resettled (excluding
tDISTLOCK).
N
Normal
Test
tCTL
3 ms
Time from when S0, S1, or S2 is changed until
CLK/CLK# output has resettled (excluding
tDISTLOCK).
B,D
Normal or Clk Stop
PWR_DWN
#
tPOWERDN
1 ms
Time from PWR_DWN# falling edge to the device
in PWR_DWN#.
Figure 5 shows that the CLK Stop to Normal transition goes
through three phases. During tCLKON, the clock output is not
specified and can have glitches. For tCLKON<t<tCLKSETL, the
clock output is enabled and must be glitch-free. For
t>tCLKSETL, the clock output phase must be settled to within
20 cycles Time from STOP# rising edge to CLK/CLK# output settled to within 50 ps of the phase before
CLK/CLK# was disabled.
50 ps of the phase before the clock output was disabled. At
this time, the clock output must also meet the voltage and timing specifications of Table 13. The outputs are in a high-impedance state during the Clk Stop mode.
Table 8. Distributed Loop Lock Time Specification
Symbol
tDISTLOCK
Min.
Max.
Unit
Description
5
ms
Time from when CLK/CLK# output is settled to when the phase error between
SYNCLKN and PCLKM falls within the tERR,PD spec in Table 13.
Document #: 38-07232 Rev. *B
Page 8 of 14
W234
Table 9. Supply and Reference Current Specification
Parameter
Description
Min.
Max.
Unit
IPOWERDOWN
“Supply” current in Power-Down state (PWR_DWN# = 0)
--
1.2
mA
ICLKSTOP
“Supply” current in Clk Stop state (STOP# = 0)
--
175
mA
INORMAL
“Supply” current in Normal state
(STOP# = 1,PWR_DWN# = 1)
--
225
mA
IREF,PWDN
Current at VDDIR or VDDIPD reference pin in PWR_DWN#
state (PWR_DWN# = 0)
--
50
µA
IREF,NORM
Current at VDDIR or VDDIPD reference pin in Normal or Clk
Stop state (PWR_DWN# = 1)
--
4
mA
Min.
Max.
Unit
Table 10 represents stress ratings only, and functional operation at the maximums is not guaranteed.
Table 10. Absolute Maximum Ratings
Parameter
Description
VDD, ABS
Max. voltage on VDD with respect to ground
–0.5
4.0
V
VI, ABS
Max. voltage on any pin with respect to ground
–0.5
VDD+0.5
V
Table 11 gives the nominal values of the external components and their maximum acceptable tolerance, assuming ZCH=28Ω.
Table 11. External Component Values
Parameter
Description
Test Load
Recommended
Value
Tolerance
Unit
RS
Serial Resistor
47
39
±5%
Ω
RP
Parallel Resistor
47
51
±5%
Ω
CF
Edge Rate Filter Capacitor
Note 1
Note 1
±10%
pF
100 pF
0.1
±20%
µF
AC Ground Capacitor
CMID
Note:
1. Do not populate CF. Leave pads for future use.
Clock Output Driver
Figure 7. Example System Clock Driver Equivalent Circuit
Document #: 38-07232 Rev. *B
Page 9 of 14
W234
Table 12. Operating Conditions[2]
Parameter
Description
Min.
Max.
Unit
VDD
Supply Voltage
3.135
3.465
V
TA
Ambient Operating Temperature
0
70
°C
tCYCLE,IN
Refclk Input Cycle Time
10
40
ns
[3]
tJ,IN
Input Cycle-to-Cycle Jitter
–
250
ps
DCIN
Input Duty Cycle over 10,000 Cycles
40
60
%tCYCLE
FMIN
Input Frequency of Modulation
30
33
kHz
PMIN[4]
Modulation Index for Triangular Modulation
–
0.6
%
Modulation Index for Non-Triangular Modulation
tCYCLE,PD
Phase Detector Input Cycle Time at PCLKM & SYNCLKN
tERR,INIT
Initial Phase error at Phase Detector Inputs
DCIN,PD
–
0.5
[5]
%
30
100
ns
–0.5
0.5
tCYCLE,PD
Phase Detector Input Duty Cycle over 10,000 Cycles
25
75
tCYCLE,PD
tI,SR
Input Slew Rate (measured at 20%-80% of input voltage) for
PCLKM, SYNCLKN, and REFCLK
1
4
V/ns
CIN,PD
Input Capacitance at PCLKM, SYNCLKN, and REFCLK[6]
–
7
pF
–
0.5
pF
∆CIN,PD
Input Capacitance matching at PCLKM and
CIN,CMOS
Input Capacitance at CMOS pins (excluding PCLKM, SYNCLKN,
and REFCLK)[6]
–
10
pF
VIL
Input (CMOS) Signal Low Voltage
–
0.3
VDD
VIH
Input (CMOS) Signal High Voltage
0.7
-
VDD
VIL,R
Refclk Input Low Voltage
-
0.3
VDDIR
VIH,R
Refclk Input High Voltage
0.7
–
VDDIR
VIL,PD
Input Signal Low Voltage for PD Inputs and STOP#
–
0.3
VDDIPD
VIH,PD
Input Signal High Voltage for PD Inputs and STOP#
0.7
–
VDDIPD
VDDIR
Input Supply Reference for REFCLK
1.235
3.465
V
SYNCLKN[6]
Input Supply Reference for PD Inputs
1.235
2.625
V
VDDIPD
Notes:
2. 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.
3. Refclk jitter measured at VDDIR (nom)/2.
4. If input modulation is used: input modulation is allowed but not required.
5. The amount of allowed spreading for any non-triangular modulation is determined by the induced downstream tracking skew, which cannot exceed the skew
generated by the specified 0.6% triangular modulation. Typically, the amount of allowed non-triangular modulation is about 0.5%.
6. Capacitance measured at Freq = 1 MHz, DC bias = 0.9V and VAC < 100 mV.
Document #: 38-07232 Rev. *B
Page 10 of 14
W234
Table 13. Device Characteristics
Parameter
Description
Min.
Max.
Unit
tCYCLE
Clock Cycle Time
2.5
3.75
ns
tJ
Cycle-to-Cycle Jitter at CLK/CLK#[7]
-
60
ps
Total Jitter over 2, 3, or 4 Clock Cycles[7]
-
75
ps
-
60
ps
266-MHz Cycle-to-Cycle Jitter
[8]
[8]
-
75
ps
VX,STOP
Output Voltage during Clk Stop (STOP#=0)
1.1
2.0
V
VX
Differential Output Crossing-Point Voltage
1.3
1.8
V
1.1
1.5
V
266-MHz Total Jitter over 2, 3, or 4 Clock Cycles
[9]
VCOS
Output Voltage Swing (p-p single-ended)
VOH
Output High Voltage
-
2.5
V
VOL
Output Low voltage
0.6
-
V
IOZ,STOP
Output Current during Clk Stop (STOP# = 0)
-
500
µA
DC
Output Duty Cycle over 10,000 Cycles
40
60
%tCYCLE
tDC,ERR
Output Cycle-to-Cycle Duty Cycle Error
-
50
ps
tR,tF
Output Rise and Fall Times (measured at 20%–80% of output voltage)
300
550
ps
tCR,CF
Difference between Output Rise and Fall Times on the Same Pin of a
Single Device (20%–80%)
-
100
ps
Notes:
7. Output Jitter spec measured at tCYCLE = 2.5 ns.
8. Output Jitter Spec measured at tCYCLE = 3.75 ns.
9. VCOS = VOH–VOL.
Ordering Information
Ordering Code
Package
Name
W234
Document #: 38-07232 Rev. *B
X
Package Type
28-pin TSSOP (173 mils)
Page 11 of 14
W234
Layout Example
+3.3V Supply
FB
C4
0.005 µF
G
10 µF
C3
G
VDDIR
G
G
G
G
G
1
2
3
4
5
6G
7
8G
9
10
G
G
VDDIPD
11
12
13
14
28
27
26
G25
24
23
22
21
20
19
G 18
17
16
15
G
G
G
G
Internal Power Supply Plane
FB = Dale ILB1206 - 300 (300Ω @ 100 MHz)
G = VIA to GND plane layer
All Bypass cap = 0.1 Ceramic XR7
Document #: 38-07232 Rev. *B
Page 12 of 14
© Cypress Semiconductor Corporation, 2002. 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.
W234
Package Diagram
28-Pin Thin Small Shrink Outline Package (TSSOP, 173 mils)
Document #: 38-07232 Rev. *B
Page 13 of 14
W234
Document Title: W234 Dual Direct Rambus™ Clock Generator
Document Number: 38-07232
REV.
ECN NO.
Issue
Date
Orig. of
Change
Description of Change
**
110497
10/21/01
SZV
Change from Spec number: 38-00921 to 38-07232
*A
111647
02/07/02
IKA
Changed Table 11, added Clock Output diagram, page 8
*B
122846
12/21/02
RBI
Add Power up Requirements to Operating Conditions Information
Document #: 38-07232 Rev. *B
Page 14 of 14