Integrated
Circuit
Systems, Inc.
General Description Features
ICS9250-10
Block Diagram
Pentium II is a trademark of Intel Corporation
I
2
C 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
I
2
C selection)
- 9 SDRAM (3.3V) up to 133MHz
- 8 PCI (3.3 V) @33.3MHz
- 2 IOAPIC (2.5V) @16.67 or 33.3MHz
- 2 Hublink clocks (3.3 V) @ 66.6 MHz
- 2 USB (3.3V) @ 48 MHz ( Non spread spectrum)
- 1 REF (3.3V) @ 14.318 MHz
Supports spread spectrum modulation ,
down spread 0 to -0.5%
I
2
C 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 I
2
C 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 = PLL core
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.
