ICS9248-73 Datasheet, PDF (1/15 Pages) Integrated Circuit Systems – Frequency Timing Generator for Pentium II Systems

Integrated
Circuit
Systems, Inc.
ICS9248 - 73
Frequency Timing Generator for Pentium II Systems
General Description
The ICS9248-73 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 ICS9248-73
employs a proprietary closed loop design, which tightly
controls the percentage of spreading over process and
temperature variations.
Block Diagram
Features
• Generates the following system clocks:
- 2 - CPUs @ 2.5V , up to 150MHz.
- 1 - IOAPIC @ 2.5V, PCI/2MHz.
- 9 - SDRAMs @ 3.3V, up to 150MHz.
- 2 - 3V66 @ 3.3V, 2x PCI MHz.
- 8 - PCIs @ 3.3V.
- 2 - 48MHz, @ 3.3V fixed.
- 1 - REF @ 3.3V, 14.318MHz.
- 1 - 24_48MHz, @ 3.3V fixed.
• Supports spread spectrum modulation ,
down spread 0 to -0.5%, ±0.25% center spread.
• I²C support for power management
• Efficient power management scheme through PD#
• Uses external 14.138 MHz crystal
Pin Configuration
Pentium II is a trademark of Intel Corporation
I²C is a trademark of Philips Corporation
9248-73 Rev B 2/10/00
48-Pin 300 mil SSOP
*120K ohm pull-up to VDD on indicated inputs.
**60K ohm pull-up to VDD on indicated inputs.
1. These pins will have 2x drive strength
Power Groups
GNDREF, VDDREF = REF & Crystal
GND3V66, VDD3V66 = 3V66
GNDPCI, VDDPCI = PCICLK
GNDCOR, VDDCOR = PLL core
GND48, VDD48 = 48MHz
GNDSDR, VDDSDR = SDRAM
GNDLCPU, VDDLCPU = CPUCLK
GNDAPIC, VDDAPIC = IOAPIC
ICS reserves the right to make changes in the device data identified in
this publication without further notice. ICS advises its customers to
obtain the latest version of all device data to verify that any
information being relied upon by the customer is current and accurate.