ICS9158-01CN24LF - Integrated Device Technology

Integrated

Circuit

Systems, Inc.

General Description Features

ICS9158-01

Block Diagram

ICS9158-01RevB 05/30/97P

The ICS9158-01 is a low cost frequency generator designed

specifically for desktop and notebook PC applications. Eight

high drive, skew-controlled copies of the CPU clock are

avail-able, eliminating the need for an external buffer.

Each high drive (50mA) output is capable of driving a 30pf

load and has a typical duty cycle of 50/50. The CPU clock

outputs are skew-controlled to within ±250ps. The CPU

clocks provide all necessary frequencies for 286, 386, 486

and Pentium systems, including support for the latest speeds

of processors.

The CPU clock offers the unique feature of smooth, glitch-

free transitions from one frequency to the next, making this

the ideal device to use whenever slowing the CPU speeds. The

ICS9158-01 makes a gradual transition between frequencies

so that it meets the Intel cycle-to-cycle timing specification

for 486 systems.

• Eight skew-free, high drive CPU clock outputs

• Up to 100 MHz output at 5V

• ±250ps skew between CPU and 2XCPU outputs

• Outputs can drive up to 30pf load

• 50mA output drivers

• Typical 50/50 duty cycle

• Compatible with 486 and Pentium CPUs

• Glitch-free start and stop clock option

• Optional power-down mode supports Energy Star

(“green”) PCs

• On-chip loop filter components

• Low power, high speed 0.8µCMOS technology

• 24-pin PDIP or SOIC package

Integrated Buffer and Motherboard Frequency Generator

Functionality

Clock ICS9158-01 (MHz)

BUSCLK

FDCLK

14.318

CPUCLK

2XCPUCLK 4,8,30,20,25,33.3,40, or 50

8,16,60,40,50,66.6,80, or 100

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.

ICS9158-01

Pin Configuration

Pin Descriptions for ICS9158-01

24-Pin PDIP or SOIC

PIN NUMBER PIN NAME TYPE DESCRIPTION

1 CPU2 Output CPU clock output

2 X14OUT - Crystal connection

3 X14IN - Crystal connection

4 VDD - Digital POWER SUPPLY (+5V)

5 GND - Digital GROUND

6 16 MHz Output 16 MHz clock output

7 24 MHz Output 24 MHz floppy disk/combination I/O clock output

8 CPU3 Output CPU clock output

9 AGND - ANALOG GROUND

10 OE Input OUTPUT ENABLE. Tristates all outputs when low.

11 CPU5 Output CPU clock output

12 GND - Digital GROUND

13 CPU7 Output CPU clock output

14 CPU6 Output CPU clock output

15 S2 Input CPU clock frequency select 2

16 AVDD - ANALOG power supply (+5V)

17 CPU4 Output CPU clock output

18 14.318 MHz Output 14.318 MHz clock output

19 GND - Digital GROUND

20 VDD - Digital POWER SUPPLY (+5V)

21 2XCPU Output 2X CPU clock output

22 CPU1 Output CPU clock output

23 FS1 Input CPU clock frequency select #1

24 FS0 Input CPU clock frequency select #0

ICS9158-01

Electrical Characteristics at 5V

Absolute Maximum Ratings

AVDD, VDD referenced to GND . . . . . . . . . . . . . . . . 7V

Operating temperature under bias. . . . . . . . . . . . . . . . 0°C to +70°C

Storage temperature . . . . . . . . . . . . . . . . . . . . . . . . . . -40°C to +150°C

Voltage on I/O pins referenced to GND. . . . . . . . . . . GND -0.5V to VDD +0.5V

Power dissipation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.5 Watts

Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating

only and functional operation of the device at these or any other conditions above those indicated in the operational sections

of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect product

reliability.

VDD = +5V±10%, TA=0°C to 70°C unless otherwise stated

Note 1: Parameter is guaranteed by design and characterization. Not 100% tested in production.

DC Characteristics

PARAMETER SYMBOL TEST CONDITIONS MIN TYP MAX UNITS

Input Low Voltage VIL 0.8 V

Input High Voltage VIH 2.0 V

Input Low Current IIL VIN=0V -5 5 µA

Input High Current IIH VIN=VDD -5 5 µA

Output Low Voltage VOL IOL=20.0mA 0.25 0.4 V

Output High Voltage1VOH IOH=-30mA 2.4 3.5 V

Output Low Current1IOL VOL=0.8V 45 65 mA

Output High Current1IOH VOH=2.0V -55 -35 mA

Supply Current IDD No load, 80 MHz 43 65 mA

Output Frequency Change over

Supply and Temperature1FDWith respect to typical

frequency 0.002 0.01 %

Short circuit current1ISC Each output clock 25 56 mA

Pull-up resistor value1RPU Input pin 680 kΩ

Input Capacitance1CiExcept X1, X2 8 pf

Load Capacitance1CLPins X1, X2 20 pf

ICS9158-01

Electrical Characteristics (

continued

)

VDD = +5V±10%, TA=0°C to 70°C unless otherwise stated

Note 1: Parameter is guaranteed by design and characterization. Not 100% tested in production.

AC Characteristics

PARAMETER SYMBOL TEST CONDITIONS MIN TYP MAX UNITS

Output Rise time, 0.8 to 2.0V

(Note 1) tr30pf load - 1 2 ns

Rise time, 20% to 80% VDD1tr30pf load - 2.5 3 ns

Output Fall time, 2.0 to 0.8V 1tf30pf load - 0.5 1 ns

Fall time, 80% to 20% VDD1tf30pf load - 1.5 2 ns

Duty cycle1dt30pf load 40/60 48/52 60/40 %

Jitter, one sigma1tj1s As compared with clock

period

0.5 2.0 %

Jitter, absolute tjab 25%

Jitter, absolute tjab 16-100 MHz clocks 500 ps

Input Frequency fi14.318 MHz

Clock skew between CPU and

2XCPU outputs Tsk 100 250 ps

Frequency Transition time1tft From 4 to 50 MHz 13 20 ms

ICS9158-01

Frequency Transitions

CPU Clock Decoding Table

(using 14.318 MHz input. All frequencies in MHz)

CLOCK#2 CPU and 2XCPU

*5V only

Peripheral Clocks

Reference Clock

A key feature of the ICS9158-01 is its ability to provide

smooth, glitch-free frequency transitions on the CPU and

2XCPU clocks when the frequency select pins are changed.

The frequency transition rate does not violate the Intel 486 or

Pentium specification of less than 0.1% frequency change

per clock period.

Using an Input Clock as a Reference

The ICS9158-01 is designed to accept a 14.318 MHz crystal

as the input reference. With some external changes, it is

possible to use a crystal oscillator or other clock sources.

Please see application note AAN04 for details on driving the

ICS9158-01 with a clock.

Stop Clock Feature (Optional Mask Version)

The ICS9158-01 incorporates a unique stop clock feature

compatible with static logic processors. When the stop clock

pin goes low, the CPUCLK will go low after the next occurring

falling edge. When STOPCLK again goes high, CPUCLK

resumes on the next rising edge of the internal clock. This

feature enables fast, glitch-free starts and stops of the

CPUCLK and is useful in Energy Start motherboard

applications.

FS2

(Pin 15) FS1

(Pin 23) FS0

(Pin 24) 2XCPU

(Pin 21) CPU

7.580

15.511

59.875

40.090

50.113

66.476

79.772*

100.226*

3.790

7.756

29.938

20.045

25.057

33.238

39.886*

50.113*

REFCLK1

(Pin 18)

14.318

BUSCLK

(Pin 6) FDCLK

(Pin 7)

16.002 24.003

ICS9158-01

24-DIP P ac ka ge

Ordering Information

ICS9158-01CN24

Example:

ICS XXXX-PPP M

Package Type

N=DIP (Plastic#)

Pattern Number (2 or 3 digit number for parts with ROM code patterns)

Device Type (consists of 3 or 4 digit numbers)

Prefix

ICS, A V=Standard Device; GSP=Genlock Device

ICS9158-01

Ordering Information

ICS9158-01CM24

Example:

ICS XXXX-PPP M

Package Type

M=SOIC

Pattern Number (2 or 3 digit number for parts with ROM code patterns)

Device Type (consists of 3 or 4 digit numbers)

Prefix

ICS, A V=Standard Device; GSP=Genlock Device

24 Lead SOIC

LEAD COUNT 24L

DIMENSION L 0.604

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.