ICS950104 Datasheet, PDF (1/19 Pages) Integrated Circuit Systems – Programmable System Clock Chip for PIII Processor

Integrated
Circuit
Systems, Inc.
ICS950104
Advance Information
Programmable System Clock Chip for PIII™ Processor
Recommended Application:
SIS630ST style chipset
Output Features:
• 1 - CPU clocks @ 2.5V
• 1 - Pair of differential CPU clocks @ 3.3V
• 9 - SDRAM @ 3.3V
• 7 - PCI @3.3V
• 1 - 48MHz, @3.3V
• 1 - 24/48MHz @ 3.3V
• 3 - REF @3.3V, (selectable strength) through I²C
Features:
• Programmable ouput frequency
• Programmable ouput rise/fall time
• Programmable CPU, SDRAM, and PCI skew
• Real time system reset output
• Spread spectrum for EMI control typically
by 7dB to 8dB, with programmable spread percentage
• Watchdog timer technology to reset system
if over-clocking causes malfunction
• Uses external 14.318MHz crystal
Skew Specifications:
• CPU - CPU: <250ps
• PCI - PCI: <500ps
• SDRAM - SDRAM: <250ps
• CPU - SDRAM:<350ps
• CPU - PCI: <3ns
Block Diagram
PLL2
X1
XTAL
X2
OSC
PLL1
Spread
Spectrum
SDATA
SCLK
FS(3:0)
PD#
PCI_STOP#
CPU_STOP#
MODE
MULTSEL
Control
Logic
Config.
Reg.
/2
CPU
DIVDER
Stop
SDRAM
DIVDER
Stop
PCI
DIVDER
Stop
48MHz
24_48MHz
3 ^REF(2:0)
CPUCLKT0
CPUCLKC0
CPUCLK
10 ^{SDRAM (9:0)}
6 ^{PCICLK (5:0)}
PCICLK_F
Pin Configuration
CPUCLKC0
1
48
CPUCLKT0
2
47
VDDCPU
3
46
GND
4
45
AVDD
5
44
X1
6
43
X2
7
42
**FS0/REF0
8
41
VDDREF
9
40
**FS1/REF1
10
39
REF2
11
38
GND
12
37
*FS2/PCICLK_F
13
36
PCICLK0
14
35
PCICLK1
15
34
PCICLK2
16
33
GND
17
32
VDDPCI
18
31
PCICLK3
19
30
PCICLK4
20
29
PCICLK5
21
28
AVDD48
22
27
**MULTSEL/24_48MHz
23
26
**FS3/48MHz
24
25
GND
IREF
GND
CPUCLK
VDDL
SDATA
SDRAM_STOP#*
SDRAM0
SDRAM1
SDRAM2
SDRAM3
VDD
GND
SDRAM4
SDRAM5
SDRAM6
SDRAM7
GND
VDD
PCI_STOP#*
CPU_STOP#*
PD#/Vtt_PWRGD#*
SCLK
GND
48-Pin 300mil SSOP
Notes:
REF0 can be 1X or 2X strength controlled by I²C.
* Internal Pull-up Resistor of 120K to VDD
** Internal Pull-down of 120K to GND
Functionality
FS3 FS2
FS1
FS0
CPU
(MHz)
SDRAM
(MHz)
PCICLK
(MHz)
0 0 0 0 66.6
100.0
33.3
0 0 0 1 100.0 100.0
33.3
0 0 1 0 150.0 100.0
37.5
0 0 1 1 133.3 100.0
33.3
0 1 0 0 66.8
133.6
33.4
0 1 0 1 100.0 133.3
33.3
0 1 1 0 100.0 150.0
37.5
0 1 1 1 133.3 133.3
33.3
1 0 0 0 66.8
66.8
33.4
1 0 0 1 97.0
97.0
32.3
1 0 1 0 70.0
105.0
35.0
1 0 1 1 95.0
95.0
31.7
1 1 0 0 95.0
126.7
31.7
1 1 0 1 112.0 112.0
37.3
1 1 1 0 97.0
129.3
32.2
1 1 1 1 96.2
96.2
32.1
950104 Rev - 09/11/01
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ADVANCE INFORMATION documents contain information on products
in the formative or design phase development. Characteristic data and
other specifications are design goals. ICS reserves the right to change or
discontinue these products without notice.