Integrated

Circuit

Systems, Inc.

General Description

Features

ICS9148B-04

Block Diagram

Pentium is a trademark of Intel Corporation

9148-04 RevB01/20/98

Pin Configuration

•

3.3Voutputs: SDRAM, PCI, REF, 48/24MHz

•

2.5V or 3.3V outputs: CPU, IOAPIC

•

20 ohm CPU clock output impedance

•

20 ohm PCI clock output impedance

•

Skew from CPU (earlier) to PCI clock - 1 to 4 ns, center

2.6 ns.

•

•

±250 ps CPU, PCI clock skew

•

400ps (cycle to cycle) CPU jitter

•

Smooth frequency switch, with selections from 50 to 83.3

MHzCPU.

•

2ms power up clock stable time

•

Clock duty cycle 45-55%.

•

48 pin 300 mil SSOP package

•

3.3V operation, 5V tolerant input.

48-Pin SSOP

Power Groups

VDD1 = REF (0:1), X1, X2

VDD2 = PCICLK_F, PCICLK(0:5)

VDD3 = SDRAM (0:11), supply for PLL core,

24MHz, 48MHz

VDDL1 = IOAPIC

VDDL2 = CPUCLK (0:3)

* Internal Pull-up Resistor of

240K to 3.3V on indicated inputs

The ICS9148B-04 generates all clocks required for high

speed RISC or CISC microprocessor systems such as Intel

PentiumPro or Cyrix. Eight different reference frequency

multiplying factors are externally selectable with smooth

frequency transitions.

Features include four CPU, seven PCI and Twelve SDRAM

clocks. Two reference outputs are available equal to the

crystal frequency. Plus the IOAPIC output powered byVDDL1.

One 48 MHz for USB, and one 24 MHz clock for Super IO.

Spread Spectrum built in - ±1.5% modulation to reduce the

functions, stop clock programing and Frequency selection.

Rise time adjustment for VDD at 3.3V or 2.5V CPU.

Additionally, the device meets the Pentium power-up

stabilization, which requires that CPU and PCI clocks be

stable within 2ms after power-up. It is not recommended to

use I/O dual function pin for the slots (ISA, PCI, CPU, DIMM).

The add on card might have a pull up or pull down.

ICS reserves the right to make changes in the device data identified in this

publication without further notice. ICS advises its customers to obtain the latest

version of all device data to verify that any information being relied upon by the

customer is current and accurate.