Frequency Generator & Integrated Buffers
Integrated Circuit Systems, Inc.
ICS9248-64
AMD-K7TM System Clock Chip
General Description
The ICS9248-64 is a main cl...
Description
Integrated Circuit Systems, Inc.
ICS9248-64
AMD-K7TM System Clock Chip
General Description
The ICS9248-64 is a main clock synthesizer chip for AMDK7 based systems. This provides all clocks required for such a system when used with a Zero Delay Buffer Chip such as the ICS9179-06. Spread Spectrum may be enabled by driving the SPREAD# pin active. Spread spectrum typically reduces system EMI by 8dB to 10dB. This simplifies EMI qualification without resorting to board design iterations or costly shielding. The ICS9248-64 employs a proprietary closed loop design, which tightly controls the percentage of spreading over process and temperature variations.
Features
Generates the following system clocks: - 3 differential pair open drain CPU clocks (1.5V external pull-up; up to 133MHz). - 8 PCI including 1 free running (3.3V) @33.3MHz. - 2 AGP(3.3V) up to 66.6MHz. - 2 REF(3.3V)@14.318MHz - 1 48MHz(3.3V) - 24 / 48MHz(3.3V) Skew characteristics: - CPU -CPU<250ps - CPUt - CPUc <200ps (differential pair) - PCI – PCI: <500ps - CPU – SDRAM_OUT: < 250ps - CPU – AGP <500ps Efficient Power Management through PD#, PCI_STOP# and CPU_STOP#. Spread Spectrum option for EMI reduction (-1.0% down spread). Uses external 14.318 MHz crystal
Block Diagram
Pin Configuration
*FS0/REF0 *FS1/REF1 GNDREF X1 X2 GNDPCI PCICLK_F PCICLK0 VDDPCI PCICLK1 PCICLK2 GNDPCI PCICLK3 PCICLK4 VDDPCI PCICLK5 PCICLK6 VDDAGP AGP0 AGP1 GNDAGP VDD48 48MHz SEL24_48#/24-48MHz 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 ...
Similar Datasheet