ICS9148-46

· Generates system clocks for CPU, PCI, 14.314 MHz, 48 and 24MHz.
· Supports single or dual processor systems
· Skew from CPU (earlier) to PCI clock 1 to 4ns
· Separate 2.5V and 3.3V supply pins
· 2.5V outputs: CPU
· 3.3V outputs: PCI, REF
· No power supply sequence requirements
· 28 pin SSOP
· Spread Sectrum operation optional for PLL1
· CPU frequencies to 100MHz are supported.

Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.0 V
Logic Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . GND –0.5 V to VDD +0.5 V
Ambient Operating Temperature . . . . . . . . . . . . 0°C to +70°C
Storage Temperature . . . . . . . . . . . . . . . . . . . . . . –65°C to +150°C

Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. These ratings are stress specifications only and functional operation of the device at these or any other conditions above those listed in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect product reliability.

The ICS9148-46 is part of a reduced pin count two-chip clock solution for designs using an Intel BX style chipset. Companion SDRAM buffers are ICS9179-03, and -12.

There are two PLLs, with the first PLL capable of spread spectrum operation. Spread spectrum typically reduces system EMI by 8-10dB. The second PLL provides support for USB (48MHz) and 24MHz requirements. CPU frequencies up to 100MHz are supported.

The I2C interface of the ICS9148-46 allows stop clock programming, frequency selection, and spread spectrum operation to be programmed. Clock outputs include two CPU (2.5V or 3.3V), five PCI (3.3V), two REF (3.3V), one 48MHz, and one selectable 48_24MHz.