
Desktop/Notebook Frequency Generator
W48S87-72
Cypress Semiconductor Corporation
3901 North First Street
San Jose
CA 95134
408-943-2600
August 4, 2000 rev. *A
Features
Maximized EMI suppression using Cypress’s Spread
Spectrum technology
±0.5% Spread Spectrum clocking
Equivalent to the W48S67-72 with Spread Spectrum for
Tilamook, MMO, and Deschutes processors
Generates system clocks for CPU, IOAPIC, SDRAM,
PCI, USB plus 14.318-MHz (REF0:1)
Serial data interface (SDATA, SCLOCK inputs) provides
additional CPU/PCI clock frequency selections, individ-
ual output clock disabling and other functions
MODE input pin selects optional power management
input control pins (reconfigures pins 26 and 27)
Two fixed outputs separately selectable as 24-MHz or
48-MHz (default = 48-MHz)
V
DDQ3
= 3.3V±5%, V
DDQ2
= 2.5V±5%
Uses external 14.318-MHz crystal
Available in 48-pin SSOP (300 mils)
10
CPU output impedance
Table 1. Pin Selectable Frequency
[1]
CPU, SDRAM
Clocks (MHz)
Note:
1.
Additional frequency selections provided by serial data interface; refer to
Table 5
on page 8.
60/66_SEL
PCI Clocks
(MHz)
0
60
30
1
66.8
33.4
Block Diagram
Pin Configuration
VDDQ3
REF0
VDDQ2
IOAPIC
VDDQ2
CPU0
CPU1
CPU2
CPU3
SDRAM0
SDRAM1
SDRAM2
SDRAM3
SDRAM4
SDRAM5
SDRAM6
SDRAM7
PCI_F
PCI0
XTAL
OSC
PLL Ref Freq
PLL 1
60/66_SEL
MODE
X2
X1
REF1
VDDQ3
Stop
Output
Control
Stop
Output
Control
PCI1
PWR_DWN#
Power
Down
Control
PCI2
PCI3
PCI4
PCI5
48/24MHZ
48/24MHZ
PLL2
÷2
I/O
Control
CPU_STOP#
REF1
REF0
GND
X1
X2
MODE
VDDQ3
PCI_F
PCI0
GND
PCI1
PCI2
PCI3
PCI4
VDDQ3
PCI5
GND
60/66_SEL
SDATA
SCLOCK
VDDQ3
48/24MHZ
48/24MHZ
GND
W
VDDQ3
CPU2.5#
VDDQ2
IOAPIC
PWR_DWN#
GND
CPU0
CPU1
VDDQ2
CPU2
CPU3
GND
SDRAM0
SDRAM1
VDDQ3
SDRAM2
SDRAM3
GND
SDRAM4
SDRAM5
VDDQ3
SDRAM6/CPU_STOP#
SDRAM7/PCI_STOP#
VDDQ3
48
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24