W48C101-01 Datasheet, PDF (1/8 Pages) Cypress Semiconductor – Spread Spectrum BX System Frequency Generator

PRELIMINARY
W48C101-01
Spread Spectrum BX System Frequency Generator
Features
• Maximized EMI suppression using Cypress’s Spread
Spectrum technology
• Four copies of CPU output
• Eight copies of PCI output (Synchronous w/CPU
output)
• Two copies of 14.318-MHz IOAPIC output
• Two copies of 48-MHz USB output
• 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 capability
Key Specifications
Supply Voltages: ....................................... V_DDQ3 = 3.3V±5%
V_DDQ2 = 2.5V±5%
CPU0:3 Jitter (Cycle to Cycle): ................................... 200 ps
Block Diagram
X1
XTAL
X2
OSC
PLL Ref Freq
VDDQ3
REF0
REF1
REF2
VDDQ2
APIC0
APIC1
CPU_STOP#
SEL100/66#
SEL0
SEL1
SPREAD#
PCI_STOP#
Stop
Clock
Control
PLL 1
÷2/÷3
Stop
Clock
Control
VDDQ2
CPU0
CPU1
CPU2
CPU3
VDDQ3
PCI_F
PCI1
PCI2
PCI3
CPU0:3 Clock Skew: ...................................................175 ps
PCI_F, PCI1:7 Clock Skew: ......................................... 500 ps
CPU to PCI Clock Skew: .............. 1.5 to 4.0 ns (CPU Leads)
Logic inputs have 250-kΩ pull-up resistors except SEL100/66#.
Table 1. Pin Selectable Frequency
SEL
CPU PCI
100/66# SEL1 SEL0 (MHz) (MHz) SPREAD#=0
0
0
0 HI-Z HI-Z Don’t Care
0
0
1 66.6 33.3 ±0.9% Center
0
1
0 66.6 33.3 –1% Down
0
1
1 66.6 33.3 –0.5% Down
1
0
0 X1/2 X1/6 Don’t Care
1
0
1
100 33.3 ±0.9% Center
1
1
0
100 33.3 –1% Down
1
1
1
100 33.3 –0.5% Down
Pin Configuration
REF0 1
REF1 2
GND 3
X1 4
X2 5
GND 6
PCI_F 7
PCI1 8
VDDQ3 9
PCI2 10
PCI3 11
GND 12
PCI4 13
PCI5 14
VDDQ3 15
PCI6 16
PCI7 17
GND 18
VDDQ3 19
GND 20
VDDQ3 21
48MHz 22
48MHz 23
GND 24
48 VDDQ3
47 REF2
46 VDDQ2
45 APIC0
44 APIC1
43 GND
42 NC
41 VDDQ2
40 CPU0
39 CPU1
38 GND
37 VDDQ2
36 CPU2
35 CPU3
34 GND
33 VDDQ3
32 GND
31 PCI_STOP#
30 CPU_STOP#
29 PWR_DWN#
28 SPREAD#
27 SEL0
26 SEL1
25 SEL100/66#
PWR_DWN#
Power
Down
Control
PLL2
PCI4
PCI5
PCI6
PCI7
VDDQ3
48MHz
48MHz
Cypress Semiconductor Corporation • 3901 North First Street • San Jose • CA 95134 • 408-943-2600
October 7, 1999, rev. **