W149
440BX AGPset Spread Spectrum Frequency Synthesizer
VDDQ3:.....................................................................3.3V±5%
Features
VDDQ2:.....................................................................2.5V±5%
• Maximized EMI suppression using Cypress’s Spread
Spectrum Technology
SDRAMIN to SDRAM0:12 Delay:..........................3.7 ns typ.
• Single chip system frequency synthesizer for Intel®
Table 1. Mode Input Table[1]
440BX AGPset
• Two copies of CPU output
• Six copies of PCI output
• One 48-MHz output for USB
Mode
Pin 2
PCI_STOP#
REF0
0
1
• One 24-MHz output for SIO
• Two buffered reference outputs
• One IOAPIC output
• Thirteen SDRAM outputs provide support for 3 DIMMs
• Spread Spectrum feature always enabled
• SMBus interface for programming
• Power management control inputs
• Smooth CPU frequency switching from 66.8–124 MHz
Table 2. Pin Selectable Frequency
Input Address
CPU0:1
(MHz)
PCI_F, 1:5
(MHz)
FS2 FS1 FS0
Spread%
1
1
1
1
0
0
0
0
1
1
0
0
1
1
0
0
1
0
1
0
1
0
1
0
100
33.3 (CPU/3)
(Reserved)
–0.5
100
103
66.8
83.3
66.8
124
33.3 (CPU/3)
34.3 (CPU/3)
33.4 (CPU/2)
41.7 (CPU/2)
33.4 (CPU/2)
41.3 (CPU/3)
±0.5
–0.5
–0.5
–0.5
±0.5
–0.5
Key Specifications
CPU Cycle-to-Cycle Jitter: ......................................... 250 ps
CPU to CPU Output Skew: ........................................ 175 ps
PCI to PCI Output Skew: ............................................ 500 ps
[2]
Logic Block Diagram
Pin Configuration
VDDQ3
VDDQ3
REF0/(PCI_STOP#)
GND
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
48
VDDQ2
IOAPIC
REF1/FS2*
GND
CPU0
CPU1
VDDQ2
OE
SDRAM12
GND
SDRAM0
SDRAM1
VDDQ3
SDRAM2
SDRAM3
GND
SDRAM4
SDRAM5
VDDQ3
SDRAM6
SDRAM7
VDDQ3
48MHz/FS0*
24MHz/FS1*
REF0/(PCI_STOP#)
REF1/FS2
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
X1
X2
XTAL
OSC
X1
X2
PLL Ref Freq
VDDQ3
PCI_F/MODE
PCI1
VDDQ2
IOAPIC
I/O Pin
Control
GND
PCI2
PCI3
PCI4
VDDQ2
PCI5
VDDQ3
SDRAMIN
GND
CPU0
CPU1
PLL 1
SDRAM11
SDRAM10
VDDQ3
SDRAM9
SDRAM8
GND
÷2/÷3
VDDQ3
PCI_F/MODE
PCI1
PCI2
SDATA
SCLK
Stop
Clock
SMBus
{
PCI3
Control
PCI4
PCI5
SDATA
SCLK
SMBus
Logic
VDDQ3
48MHz/FS0
PLL2
÷2
24MHz/FS1
VDDQ3
SDRAM0:12
SDRAMIN
13
Intel is a registered trademark of Intel Corporation.
Notes:
1. Mode input latched at power-up.
2. Internal pull up resistors(*) should not be relied upon for setting I/O pins HIGH. Pin function with parentheses determined by MODE pin resistor strapping.
Cypress Semiconductor Corporation
•
3901 North First Street
•
San Jose
•
CA 95134
•
408-943-2600
Document #: 38-07176 Rev. *A
Revised December 22, 2002