W48S101-04 Datasheet, PDF (1/12 Pages) Cypress Semiconductor – Spread Spectrum Motherboard Frequency Generator

PRELIMINARY
W48S101-04
Spread Spectrum Motherboard Frequency Generator
Features
Key Specifications
• Maximized EMI suppression using Cypress’s Spread
Spectrum technology
• I²C™ interface
• Four copies of CPU output
• Eight copies of PCI clock (synchronous w/CPU output)
• Two copies of 14.318-MHz IOAPIC output
• One copy of 48-MHz USB output
• Selectable 24-/48-MHz clock-through-resistor
strapping
• Three buffered copies of 14.318-MHz reference input
• Input is a 14.318-MHz XTAL or reference signal
• Selectable 100-MHz or 66-MHz CPU outputs
• Power management control input pins
• Test mode and output three-state through I²C interface
Supply Voltages:....................................... V_DDQ3 = 3.3V±5%
V_DDQ2 = 2.5V±5%
CPU Cycle to Cycle Jitter: ........................................... 200 ps
CPU0:3 Output Skew: ................................................ 175 ps
PCI_F, PCI1:7 Output Skew: .......................................500 ps
CPU to PCI Output Skew: ............ 1.5 to 4.0 ns (CPU Leads)
Logic inputs and REF0/SEL48# have 250K pull-up resistors
except SEL100/66#.
Table 1. Pin Selectable Frequency
SEL
100/66#
PCI
CPU (MHz) (MHz)
SPREAD#=0
0
66.8
33.4
±0.5% Center
1
100
33.3
±0.5% Center
Block Diagram
X1
X2
VDDCORE0/1
GNDCORE0/1
XTAL
OSC
PLL Ref Freq
CPU_STOP#
100/66#_SEL
SPREAD#
PCI_STOP#
Stop
Clock
Control
PLL 1
÷2/÷3
Stop
Clock
Control
SDATA
SCLK
PWR_DWN#
I²C
Logic
Power
Down
Control
PLL2
I²C is a trademark of Philips Corporation.
VDDREF
REF0/SEL48#
REF1
REF2
GNDREF
VDDAPIC
APIC0
APIC1
GNDAPIC
VDDCPU0
CPU0
CPU1
GNDCPU0
VDDCPU1
CPU2
CPU3
GNDCPU1
VDDPCI0
PCI_F
PCI1
PCI2
PCI3
GNDPCI0
VDDPCI1
PCI4
PCI5
PCI6
PCI7
GNDPCI1
VDD48MHz
48MHz
24/48MHz
GND48MHz
Pin Configuration^[1]
REF0/SEL48# 1
REF1 2
GNDREF 3
X1 4
X2 5
GNDPCI0 6
PCICLK_F 7
PCI1 8
VDDPCI0 9
PCI2 10
PCI3 11
GNDPCI1 12
PCI4 13
PCI5 14
VDDPCI1 15
PCI6 16
PCI7 17
GNDPCI2 18
VDDCORE0 19
GNDCORE0 20
VDD48MHz 21
48MHz 22
24/48MHz 23
GND48MHz 24
48 VDDREF
47 REF2
46 VDDAPIC
45 APIC0
44 APIC1
43 GNDAPIC
42 NC
41 VDDCPU0
40 CPU0
39 CPU1
38 GNDCPU0
37 VDDCPU1
36 CPUCLK2
35 CPUCLK3
34 GNDCPU1
33 VDDCORE1
32 GNDCORE1
31 PCI_STOP#
30 CPU_STOP#
29 PWR_DWN#
28 SPREAD#
27 SDATA
26 SCLK
25 SEL100/66#
Note:
1. Internal pull-up resistors should not be relied upon for
setting I/O pins HIGH.
Cypress Semiconductor Corporation • 3901 North First Street • San Jose • CA 95134 • 408-943-2600
October 27, 1999, rev. **