ICS9250-14

Integrated Circuit Systems, Inc. ICS9250-14 Preliminary Product Preview Frequency Timing Generator for Pentium II Systems General Description The ICS9250-14 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 ICS9250-14 employs a proprietary closed loop design, which tightly controls the percentage of spreading over process and temperature variations. Features • Generates the following system clocks: - 2 - CPUs @ 2.5V, up to 150MHz. - 1 - IOAPIC @ 2.5V, PCI or PCI/2MHz. - 13 SDRAMs (3.3V) @ 150MHz. - 2 - 3V66 @ 3.3V, 2x PCIMHz. - 8 - PCIs @ 3.3V. - 1 - 48MHz, @ 3.3V fixed. - 2 - REF @ 3.3V, 14.318Hz. - 1 - 24MHz, @ 3.3V fixed. Supports spread spectrum modulation , ± .25% center spread. I2C support for power management Efficient power management scheme through PD# Uses external 14.138 MHz crystal CPU – CPU: <175ps SDRAM - SDRAM: < 250ps 3V66 – 3V66: <250ps PCI – PCI: <500ps CPU-SDRAM<500ps CPU(early)-PCI: MIN=1.0ns,TYP=2.0,MAX=4.0 CPU-3V66<500ps 3V66(early)-PCI: MIN=1.5ns,TYP=2.0,MAX=4.0 IOAPIC-PCI<500ps • • • • • • • • • • • • • Block Diagram Skew Specifications Pin Configuration Power Groups GNDREF, VDDREF = REF, Crystal GND3V66, VDD3V66 = 3V66 GNDPCI, VDDPCI = PCICLKs GNDCOR, VDDCOR = PLLCORE GND48, VDD4...