Bx Notebook System Frequency Synthesizer
W137
Cypress Semiconductor Corporation
•
3901 North First Street
•
San Jose
•
CA 95134
•
408-943-2600
October 12, 1999, rev. **
Features
• Maximized EMI suppression using Cypress’s Spread
Spectrum Technology
• Two copies of CPU output
• Six copies of PCI output (Synchronous w/CPU output)
• One 48-MHz output for USB support
• One selectable 24-/48-MHz output
• Two Buffered copies of 14.318-MHz input reference
signal
• Supports 100-MHz or 66-MHz CPU operation
• Power management control input pins
• Available in 28-pin SSOP (209 mils)
• SS function can be disabled
• See W40S11-02 for 2 SDRAM DIMM support
Key Specifications
Supply Voltages: ....................................... VDDQ3 = 3.3V±5%
VDDQ2 = 2.5V±5%
CPU0:1 Output to Output Skew: ................................ 175 ps
CPU0:1 Cycle to Cycle Jitter: ..................................... 200 ps
PCI_F, PCI1:5 Output to Output Skew:........................ 500 ps
PCI_F, PCI1:5 Cycle to Cycle Jitter: ............................ 250 ps
CPU to PCI Output Skew: ............... 1.5–4.0 ns (CPU Leads)
Output Duty Cycle: .................................................... 45/55%
PCI_F, PCI Edge Rate: .............................................. >1 V/ns
CPU_STOP#,
OE,
SPREAD#,
SEL48#,
PCI_STOP#,
PWR_DWN# all have a 250-k
Ω pull-up resistor.
Table 1. Pin Selectable Frequency
SEL100/66#
OE
CPU
PCI
Spread%
0/1
0
HI-Z
HI-Z
Don’t Care
0
1
66.6 MHz
33.3
See Table 2
1
1
100 MHz
33.3
See Table 2
Table 2. Spread Spectrum Feature
SPREAD#
Spread Profile
0
–0.5% (down spread)
1
0% (spread disabled)
Block Diagram
Pin Configuration
REF0:1
CPU0:3
CPUdiv2_0:1
3V66_0:3
XTAL
PLL 1
SPREAD#
X2
X1
PCI_F
PCI1:7
IOAPIC0:2
48MHz
PLL2
OSC
÷2
STOP
Logic
Power
Three-state
Logic
SEL0
SEL1
SEL133/100#
Clock
CPU_STOP#
÷2/÷1.5
STOP
Logic
Clock
Down
Logic
÷2
STOP
Logic
Clock
÷2
2
4
2
4
1
7
3
1
PCI_STOP#
PWRDWN#
GND
X1
X2
PCI_F
PCI1
PCI2
GND
VDDQ3
PCI3
PCI4
PCI5
VDDQ3
48MHz
24/48MHz/OE
VDDQ3
REF0/SEL48#
REF1/SPREAD#
VDDQ2
CPU0
CPU1
GND
GND
PCI_STOP#
VDDQ3
CPU_STOP#
PWR_DWN#
SEL100/66#
GND
28
27
26
25
24
23
22
21
20
19
18
17
16
15
1
2
3
4
5
6
7
8
9
10
11
12
13
14
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