AV9148F-75-T 데이터 시트보기 (PDF) - Integrated Circuit Systems

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AV9148F-75-T

Frequency Generator & Integrated Buffers for Mother Boards

Integrated Circuit Systems 

Integrated

Circuit

Systems, Inc.

ICS9148 - 75

Preliminary Product Preview

Frequency Generator & Integrated Buffers for Mother Boards

General Description

The ICS9148-75 generates all clocks required for high speed

RISC or CISC microprocessor systems such as Intel

PentiumPro™, AMD™ or Cyrix™. Sixteen different reference

frequency multiplying factors are externally selectable with

smooth frequency transitions.

Spread spectrum may be enabled through I2C programming.

Spread spectrum typically reduces system EMI by 8dB to

10dB. This simplifies EMI qualification without resorting to

board design iterations or costly shielding. The ICS9148-75

employs a proprietary closed loop design, which tightly

controls the percentage of spreading over process and

temperature variations.

Serial programming I2C interface allows changing functions,

stop clock programming and frequency selection. The

SDRAM12 output may be used as a feed back into an off chip

PLL.

Block Diagram

Features

• Generates the following system clocks:

- 3 CPU(2.5V/3.3V) up to 100MHz.

- 6 PCI(3.3V) @ 33.3MHz (including one free

running PCICLK)

- 3AGP(3.3V) @ 2 x PCI

- 13 SDRAMs(3.3V) up to 100MHz

- 1 REF (3.3V) @ 14.318MHz

- 1 - 48MHz (3.3V) fixed

• Skew characteristics:

- CPU – CPU<250ps

- CPU(early) – PCI : 1-4ns

- AGP – PCI: 250ps

- PCI – PCI <500ps

• Supports Spread Spectrum modulation & I2C

programming for Power Management, Frequency Select

• Efficient Power management scheme through power

down PCI, AGP and CPU_STOP clocks.

• Uses external 14.318MHz crystal

• 48 pin 300mil SSOP.

Pin Configuration

Power Groups

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

VDD2 = PCICLK_F, PCICLK(0:5)

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

VDD4 = AGP (1:2)

VDD5 = Fixed PLL, 48MHz , AGP0

VDDL = CPUCLK (0:3)

9148-75 Rev C 3/01/00

48-Pin SSOP

* Internal Pull-up Resistor of

240K to 3.3V on indicated inputs

Pentium is a trademark of Intel Corporation

I2C is a trademark of Philips Corporation

PRODUCT PREVIEW documents contain information on new

products in the sampling or preproduction phase of development.

Characteristic data and other specifications are subject to change

without notice.

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