
Integrated
Circuit
Systems, Inc.
General Description
Features
ICS9250-10
Block Diagram
Pentium II is a trademark of Intel Corporation
I
2C is a trademark of Philips Corporation
Frequency Timing Generator for Pentium II Systems
9250-10 Rev K 12/14/01
Pin Configuration
Generates the following system clocks:
- 3 CPU (2.5V) 66.6/100 MHz (up to 133MHz through
I2C selection)
- 9 SDRAM (3.3V) up to 133MHz
- 8PCI(3.3V)@33.3MHz
- 2IOAPIC(2.5V)@16.67or33.3MHz
- 2 Hublink clocks (3.3 V) @ 66.6 MHz
- 2 USB (3.3V) @ 48 MHz ( Non spread spectrum)
- 1REF(3.3V)@14.318MHz
Supports spread spectrum modulation ,
down spread 0 to -0.5%
I2C support for power management
Efficient power management scheme through PD#
Uses external 14.138 MHz crystal
56-Pin 300 mil SSOP
The ICS9250-10 is a single chip clock for Intel Pentium II.
It provides all necessary clock signals for such a system.
Spread spectrum may be enabled through I2C programming.
Spread spectrum typically reduces EMI by 8dB to 10 dB.
This simplifies EMI qualification without resorting to board
design iterations or costly shielding. The ICS9250-10
employs a proprietary closed loop design, which tightly
controls the percentage of spreading over process and
temperature variations.
Power Groups
VDD0,GND0=REF&Crystal
VDD1,GND1=3V66[1:0]
VDD2,GND2=PCICLK[7:0]
VDD3,GND3=PLLcore
VDD4,GND4= 48MHz[1:0]
VDD5,GND5 =SDRAM_F,SDRAM[7:0]
VDDL0,GNDL0=CPUCLK[2:0]
VDDL1,GNDL1=IOAPIC[1:0]
*60K ohm pull-up to VDD on indicated inputs.