ICS9148-02

Features:

· Generates system clocks for CPU, IOAPIC, SDRAM, PCI, plus 14.314 MHz REF(0:1), USB, Plus Super I/O
· Supports single or dual processor systems
· I²C serial configuration interface provides output clock disabling and other functions
· MODE input pin selects optional power management input control pins
· Two fixed outputs separately selectable as 24 or 48MHz
· Separate 2.5V and 3.3V supply pins
· 2.5V or 3.3V outputs: CPU, IOAPIC
· 3.3V outputs: SDRAM, PCI, REF, 48/24 MHz
· CPU 3.3_2.5# logic pin to adjust output strength
· No power supply sequence requirements
· Uses external 14.318MHz crystal
· 48 pin 300 mil SSOP
· Output enable register for serial port control: 1 = enable 0 = disable


Pinout




Specifications

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


Description

The ICS9148-02 is a Clock Synthesizer chip for Pentium and PentiumPro CPU based Desktop/Notebook systems that will provide all necessary clock timing.

Features include four CPU, seven PCI and eight SDRAM clocks. Two reference outputs of the ICS9148-02 are available equal to the crystal frequency. Additionally, the device meets the Pentium power-up stabilization, which requires that CPU and PCI clocks be stable within 2ms after power-up.

PWR_DWN# pin of the ICS9148-02 allows low power mode by stopping crystal OSC and PLL stages. For optional power management, CPU_STOP# can stop CPU (0:3) clocks and PCI_STOP# will stop PCICLK (0:5) clocks. CPU and IOAPIC output buffer strength controlled by CPU 3.3_2.5# pin to match VDDL voltage.

High drive CPUCLK outputs of the ICS9148-02 typically provide greater than 1V/ns slew rate into 20pF loads. PCICLK outputs typically provide better than 1V/ns slew rate into 30pF loads while maintaining 50±5% duty cycle. The REF clock outputs typically provide better than 0.5V/ns slew rates.

The ICS9148-02 accepts a 14.318MHz reference crystal or clock as its input and runs on a 3.3V core supply.