
Universal Clock Generator for Intel, VIA and SIS
CY28551-3
...................... Document #: 001-05677 Rev. *D Page 1 of 28
400 West Cesar Chavez, Austin, TX 78701
1+(512) 416-8500
1+(512) 416-9669
www.silabs.com
Features
Compliant to Intel CK505
Selectable CPU clock buffer type for Intel P4 or K8
selection
Selectable CPU frequencies
Universal clock to support Intel, SiS and VIA platform
0.7V Differential CPU clock for Intel CPU
3.3V Differential CPU clock for AMD K8
100-MHz differential SRC clocks
96-MHz differential dot clock
133-MHz Link clock
48-MHz USB clocks
33-MHz PCI clock
Dynamic Frequency Control
Dial-A-Frequency
WatchDog Timer
Two Independent Overclocking PLLs
Low-voltage frequency select input
I2C support with readback capabilities
Ideal Lexmark Spread Spectrum profile for maximum
electromagnetic interference (EMI) reduction
3.3V power supply
56-pin QFN packages
CPU
SRC
SATA
PCI
REF
LINK
DOT96
24_48M
48M
x 2
x 6
x1
x 6
x 3
x2
x 1
x1
x 1
Block Diagram
Pin Configuration
* Indicates internal pull-up
** indicates internal pull-down
VDD_REF
VDD_CPU
VDD_PCIEX
VTTPWR_GD#/PD
PLLReference
FS[D:A]
PLL1
CPU
VDD_DOT
PLL3
SATA
Divider
PLL4
Fixed
Divider
REF[2:0]
CPUT[1:0]
CPUC[1:0]
PCIET[6:2]
PCIEC6:2]
DOT96T/SATAT/LINK0
DOT96C/SATAC/LINK1
I2C
Logic
SDATA
SCLK
14.318-MHz
Crystal
Xin
Xout
VDD_48
48M
VDD_PCI
PCI[6:0]
DOC[2:1]
PLL2
PCIEX
VDD_SATA
PCIET0/SATAT
PCIEC0/SATAC
WDT
SRESET#
24_48M
SEL[1:0]
SEL_P4_K8
SEL24_48
Multiplexer
Controller
Divider
RESET_I#
PCI
4
/*
SELP
4_K8
VDDPCI
PC3/*FS
B
P
C
I2
/*
*F
S
A
VSSPCI
PCI
1
/P
CI
EREQ
#
A
PCI
0
/P
CI
EREQ
#
B
**
DOC1
RESET
_
I#/SRESE
T
#
R
E
F
0
/**F
S
D
R
E
F
1
/
**F
S
C
REF2/**
M
ODE
VSSREF
Xin
56 55 54 53 52 51 50 49 48 47 46 45 44 43
*SEL0/ PCI5 1
42 Xout
VDD48 2
41 VDDREF
**SEL24_48/ 24_48M 3
40 SCLK
**SEL1/48M 4
39 SDATA
VSS48 5
38 VTTPWRG#/PD
VDDDOT 637 CPUT0
LINK0/DOT96T/SATAT 7
36 CPUC0
LINK1/DOT96C/SATAC 8
35 VDDCPU
VSSDOT 9
34 CPUT1
VDDSATA 10
33 CPUC1
SATAT/PCIEXT0 11
32 VSSCPU
SATAC/PCIEXC0 12
31 **DOC2
VSSSATA 13
30 VSSA
NC 14
29 VDDA
15 16 17 18 19 20 21 22 23 24 25 26 27 28
PCI
E
XT
2
PCI
E
XC2
VDDPCIE
PCI
E
XT
3
PCI
E
XC3
VS
SPCIE
PCI
E
XT
4
PCI
E
XC4
VDDPCIE
PCI
E
XC5
PCI
E
XT
5
PCI
E
X
C6/
P
C
I_
ST
P#
PCIEXT
6
/CPU_
ST
P#
VS
SPCIE
CY28551-3