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ICS9248-126

Third party brands and names are the property of their respective owners.

The ICS9248-126 is the single chip clock solution for

Desktop/Notebook designs using the SIS 540/630 style

chipset. It provides all necessary clock signals for such a

system.

Spread spectrum typically reduces system EMI by 8dB to

10dB. This simplifies EMI qualification without resorting to

board design iterations or costly shielding. The ICS9248-126

employs a proprietary closed loop design, which tightly

controls the percentage of spreading over process and

temperature variations.

stop clock programming and frequency selection.

General Description

Power Groups

VDDREF = REF, X1, X2

VDDPCI = PCICLK_F, PCICLK

VDDSDR = SDRAM, supply for PLL core,

VDD48 = 48MHz, 24MHz

VDDLCPU = CPUCLKs

Pin Configuration

PIN NUMBER

PIN NAME

TYPE

DESCRIPTION

1, 6, 15, 19, 27, 30,

36, 42

VDD

PWR

3.3V Power supply for SDRAM output buffers, PCI output buffers,

reference output buffers and 48M Hz output

REF0

OUT

14.318 M Hz reference clock.

FS3

IN

Frequency select pin.

3, 10, 16, 22,

33, 39, 44

GND

PWR

Ground pin for 3V outputs.

4

X1

IN

Crystal input,nominally 14.318M Hz.

5

X2

OUT

Crystal output, nominally 14.318M Hz.

FS1

IN

Frequency select pin.

PCICLK0

OUT

PCI clock outputs.

FS2

IN

Frequency select pin.

PCICLK1

OUT

PCI clock outputs.

14, 13, 12, 11, 9

PCICLK (6:2)

OUT

PCI clock outputs.

41, 40, 38, 37, 35,

34, 32, 31, 29, 28,

21, 20, 18, 17

SDRAM (13:0)

OUT

SDRAM clock outputs

23

SDATA

I/O

Data pin for I

2

C circuitry 5V tolerant

24

SCLK

IN

Clock input of I2C input, 5V tolerant input

CPU2.5_3.3#

IN

Voltage select 2.5V when high - 3.3V when low

24_48M Hz

OUT

Clock output for super I/O/USB default is 24M Hz

FS0

IN

Frequency select pin.

48M Hz

OUT

48MHz output clock

43, 45, 46

CPUCLK (2:0)

OUT

CPU clock outputs.

47

VDDLCPU

PWR

Power pin for the CPUCLKs. 2.5V

48

REF1

OUT

14.318 M Hz reference clock.

26

2

7

8

25