Integrated

Circuit

Systems, Inc.

ICS951412

0883G—12/08/04

Functionality

Pin Configuration

Recommended Application:

ATI RS480 systems using AMD K8 processors

Output Features:

•

3 - 14.318 MHz REF clocks

•

1 - USB_48MHz USB clock

•

1 - HyperTransport 66 MHz clock seed

•

1 - PCI 33 MHz clock seed

•

2 - Pairs of AMD K8 clocks

•

6 - Pairs of SRC/PCI Express* clocks

•

2 - Pairs of ATIG (SRC/PCI Express) clocks

Features:

•

2 - Programmable Clock Request pins for SRC

clocks

•

Spread Spectrum for EMI reduction

•

Outputs may be disabled via SMBus

•

External crystal load capacitors for maximum

frequency accuracy

System Clock Chip for ATI RS480 K8-based Systems

CPU

HTT

PCI

MHz

MHz

MHz

0

0

0

Hi-Z

Hi-Z

Hi-Z

00

1X

X/3

X/6

0

1

0

180.00

60.00

30.00

0

1

1

220.00

73.12

36.56

1

0

0

100.00

66.66

33.33

1

0

1

133.33

66.66

33.33

1

1

1

200.00

66.66

33.33

FS1

FS0

FS2

56 Pin SSOP/TSSOP

Power Groups

VDD

GND

56

55

Xtal, REF

51

49

PCICLK output

48

46

HTTCLK output

43

42

CPU Outputs

14, 21,

32,35

15, 20,

26,31,36

SRC outputs

39

38

Analog, CPU PLL

3

5

USB_48MHz output

Pin Number

Description

X1 1

56 VDDREF

X2 2

55 GND

VDD48 3

54 **FS0/REF0

USB_48MHz 4

53 **FS1/REF1

GND 5

52 REF2

NC 6

51 VDDPCI

SCLK 7

50 PCICLK0

SDATA 8

49 GNDPCI

**FS2 9

48 VDDHTT

**CLKREQA# 10

47 HTTCLK0

**CLKREQB# 11

46 GNDHTT

SRCCLKT7 12

45 CPUCLK8T0

SRCCLKC7 13

44 CPUCLK8C0

VDDSRC 14

43 VDDCPU

GNDSRC 15

42 GNDCPU

SRCCLKT6 16

41 CPUCLK8T1

SRCCLKC6 17

40 CPUCLK8C1

SRCCLKT5 18

39 VDDA

SRCCLKC5 19

38 GNDA

GNDSRC 20

37 IREF

VDDSRC 21

36 GNDSRC

SRCCLKT4 22

35 VDDSRC

SRCCLKC4 23

34 SRCCLKT0

SRCCLKT3 24

33 SRCCLKC0

SRCCLKC3 25

32 VDDATI

GNDSRC 26

31 GNDATI

ATIGCLKT1 27

30 ATIGCLKT0

ATIGCLKC1 28

29 ATIGCLKC0

Note: Pins preceeded by '**' have a 120 Kohm Internal Pull Down resistor

*Other names and brands may be claimed as the property of others.