ICS9147-22

Features:

Generates system clocks for CPU, IOAPIC, SDRAM, PCI, plus 14.318 MHz (REF0:1), USB, Super I/O
Supports single or dual processor systems
Supports Intel 60, 66.8MHz, Cyrix 55, 75MHz plus 83.3 and 68MHz (Turbo of 66.6) speeds.
Synchronous clocks skew matched to 250ps window on CPU, SDRAM and 500ps window on PCI clocks
CPU clocks to PCI clocks skew 1-4ns (CPU early)
Two fixed outputs, 48MHz and 24 MHz
Separate 2.5V and 3.3V supply pins
- 2.5V or 3.3V output: CPU, IOAPIC
- 3.3V outputs: SDRAM, PCI, REF, 48/24 MHz
No power supply sequence requirements
48 pin 300 mil SSOP



Pinout




Specifications

Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.0 V

Logic Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . GND -0.5 V to V_DD +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.


Description

The ICS9147-22 is a Clock Synthesizer chip for Pentium and PentiumPro plus Cyrix 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 are available equal to the crystal frequency, plus the IOAPIC output powered by VDDL. Additionally, the device meets the Pentium powerup stabilization, which requires that CPU and PCI clocks be stable within 2ms after power-up.

High drive PCICLK and SDRAM outputs of the ICS9147-22 typically provide greater than 1 V/ns slew rate into 30pF loads. CPUCLK outputs typically provide better than 1V/ns slew rate into 20 pF loads while maintaining 50 ±5% duty cycle. The REF clock outputs typically provide better than 0.5V/ns slew rates.

The ICS9147-22 accepts a 14.318MHz reference crystal or clock as its input and runs on a 3.3V supply.