Clock Solution Targets Pentium Mobile Computers

A clock solution for Pentium and Pentium II class mobile computers, PI6C671 is a two PLL clock synthesizer that provides an IOAPIC and four 60/66 MHz selectable CPU clocks with their own power and ground pins to support 2.5V to 3.3V operation, seven synchronous PCI clocks, eight low-skew SDRAM clocks, three reference clocks, and two selectable 24/28 MHz clocks to support USB and super I/O. System configuration is done by an I2C two-wire serial interface used to reduce circuit noise and power consumption. The I2C serial interface control lets programmers enable/disable each clock output driver, change CPU frequencies, and select 24 or 48 MHz outputs. Power-down is supported by selectable pin options, one for putting device in power-down mode by stopping the oscillator and both PLLs, or the CPU and PCI clocks can be stopped individually.