PRELIMINARY
W144
440BX AGPset Spread Spectrum
Frequency Synthesizer
Table 1. Mode Input Table
Features
• Maximized EMI suppression using Cypress’s Spread
Spectrum technology
• Single chip system frequency synthesizer for Intel
440BX AGPset
Mode
Pin2
0
1
PCI_STOP#
REF0
®
• Two copies of CPU output
• Six copies of PCI output
• One 48-MHz output for USB
• One 24-MHz output for SIO
• Two buffered reference outputs
• One IOAPIC output
Table 2. Pin Selectable Frequency
Input Address
CPU_F, CPU1
FS3 FS2 FS1 FS0
(MHz)
PCI_F, 1:5 (MHz)
33.3 (CPU/4)
31 (CPU/4)
37.5 (CPU/4)
35 (CPU/4)
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
133.3
124
150
140
105
110
115
120
100
133.3
112
103
66.8
83.3
75
• Thirteen SDRAM outputs provide support for 3 DIMMs
• Supports frequencies up to 150 MHz
2
35 (CPU/3)
• I C™ interface for programming
36.7 (CPU/3)
38.3 (CPU/3)
40 (CPU/3)
• Power management control inputs
Key Specifications
33.3 (CPU/3)
44.43 (CPU/3)
37.3 (CPU/3)
34.3 (CPU/3)
33.4 (CPU/2)
41.7 (CPU/2)
37.5 (CPU/2)
41.3 (CPU/3)
CPU Cycle-to-Cycle Jitter: ......................................... 250 ps
CPU to CPU Output Skew: ........................................ 175 ps
PCI to PCI Output Skew: ............................................ 500 ps
V
V
: .................................................................... 3.3V±5%
: .................................................................... 2.5V±5%
DDQ3
DDQ2
SDRAMIN to SDRAM0:11 Delay: ..........................3.7 ns typ.
SDRAM0:11 (leads) to SDRAM_F Skew: ..............0.4 ns typ.
124
Logic Block Diagram
Pin Configuration
VDDQ3
VDDQ3
REF0/(PCI_STOP#)
GND
48
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
VDDQ2
1
REF0/(PCI_STOP#)
REF1/FS2
IOAPIC
2
3
REF1/FS2*
X1
X2
XTAL
OSC
X1
GND
4
PLL Ref Freq
X2
5
CPU_F
VDDQ2
IOAPIC
VDDQ3
PCI_F/MODE
PCI1/FS3
GND
6
CPU1
VDDQ2
Stop
Clock
I/O Pin
Control
7
Control
8
CLK_STOP#
SDRAM_F
GND
SDRAM0
SDRAM1
VDDQ3
SDRAM2
SDRAM3
GND
SDRAM4
SDRAM5
VDDQ3
SDRAM6
SDRAM7
VDDQ3
48MHz/FS0*
24MHz/FS1*
9
CLK_STOP#
PCI2
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
VDDQ2
PCI3
Stop
Clock
Control
PCI4
CPU1
PCI5
PLL 1
÷2,3,4
CPU_F
VDDQ3
SDRAMIN
GND
VDDQ3
PCI_F/MODE
SDRAM11
SDRAM10
VDDQ3
SDRAM9
SDRAM8
GND
PCI1/FS3
PCI2
Stop
Clock
PCI3
Control
PCI4
PCI5
2
SDATA
SCLK
I C
Logic
I2C
{
SDATA
SCLK
VDDQ3
48MHz/FS0
PLL2
Note:
÷2
1. Internal pull-up resistors should not be relied upon for setting
I/O pins HGH. Pin function with parentheses determined by
MODE pin resistor strapping. Unlike other I/O pins, input FS3
has an internal pull down resistor.
24MHz/FS1
VDDQ3
SDRAM0:11
Stop
Clock
Control
SDRAMIN
12
SDRAM_F
Intel is a registered trademark of Intel Corporation. I2C is a trademark of Philips Corporation.
Cypress Semiconductor Corporation
•
3901 North First Street
•
San Jose
•
CA 95134
•
408-943-2600
November 2, 1999, rev. **