9131-01CS16 - Integrated Device Technology

Integrated

Circuit

Systems, Inc.

General Description Features

ICS9131

Block Diagram

32 KhZ Motherboard Frequency Generator

9131 Rev B 052897P

The ICS9131 offers a tiny footprint solution for generating

a selectable CPU clock from a 32.768 kHz crystal. The device

allows a variety of microprocessors to be clocked by changing

the state of address lines FS0, FS1, and FS2. The ICS9131 is

the ideal solution for replacing high speed oscillators and for

reducing clock speeds to save power in computers. The

device provides smooth, glitch-free frequency transitions so

that the CPU can continue to operate during slow down or

speed up. The rate of frequency change makes the ICS9131

compatible with all 386DX, 386SX, 486DX, 486DXZ, 486SX

and Pentium™ microprocessors.

The ICS9131 is driven from a single 32.768 kHz crystal. The

only external components required are the crystal and a 10M

ohm resistor. The device generates the 14.318 MHz system

clock, eliminating the need for a 14.318 MHz crystal. High-

Performance applications may require high speed clock

termination components.

• Single 32.768 kHz crystal generates system clock and

selectable CPU clock

• Generates CPU clocks from 8 MHz to 100 MHz.

• Operates from 3.3V or 5.0V supply

• Operates up to 66 MHz at 3.3V

• Separate VDD for 32 kHz clock enables it to run from

battery

• STOPCLK feature allows for a glitch-free turn-on and

Pen-turn-off of the CPU clock to static processors

• Output enable tristates outputs

• 16-pin PDIP or SOIC package

• Frequency selects allow for a smooth transition of

the CPUCLK

VDD32 Supply

The ICS9131 has a separate power supply for the 32.768 kHz

oscillator circuitry. This allows the 32 kHz clock to run from

a battery or other source while the main power to the chip is

disconnected. The VDD32 supply is guaranteed to operate

down to +2.0V, with the clock consuming less than 10µA at

+3.3V and the main VDD at 0V.

The frequencies and power-down options in the ICS9131 are

mask programmable. Customer specific masks can be made

and prototypes delivered within 6-8 weeks from receipt of

order. ICS also offers standard versions, such as those de-

scribed in this data sheet.

Pentium is a trademark of Intel.

Pin Configuration

16-Pin DIP or SOIC

ICS9131

Pin Descriptions

Functionality

FS2 FS1 FS0 CPUCLK ACTUALS

33.3

66.6

16.004

25.059

33.412

40.095

50.119

60.142

66.484

80.190

PIN NUMBER PIN NAME TYPE DESCRIPTION

1 32 kHz Output 32.768 kHz output.

2 X2 Output Connect 32 kHz crystal, this input includes internal load

capacitor for crystal.

3 X1 Input Connect 32 kHz crystal, this input includes internal load

capacitor for crystal.

4 VDD32 -- Power Supply for 32 kHz oscillator.

5 VCC -- Power Supply.

6 VSS -- Ground.

7 AGND -- Analog Ground.

8 OE Input OE tristates outputs when low.

9 FS2 Input CPU clock frequency select 2.

10 REFCLK Output 14.318 M Hz output.

11 STOPCLK# Input Stops CPU clock when low.

12 VSS -- Ground.

13 VCC -- Power supply.

14 CPUCLK Output CPU clock output (see Decoding table).

15 FS1 Input CPU clock frequency select 1.

16 FS0 Input CPU clock frequency select 0.

ICS9131

Recommended External Circuit

Notes:

1) The external components shown should be placed as close to the device as possible.

2) Pins 5 and 13 should be connected together externally. One decoupling capacitor may suffice for both pins.

ICS9131

Electrical Characteristics at 5V

Absolute Maximum Ratings

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.

Operating VDD = +4.5V to +5.5V; TA =0°C to 70°C unless otherwise stated

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

Note 2: With the STOPCLK pin low (active).

Note 3: Absolute Jitter measured as the shortest and longest period difference to the mean period of the sample set.

DC Characteristics

PARAMETER SYMBOL TEST CONDITIONS MIN TYP MAX UNITS

Input Low Voltage VIL --0.8V

Input High Voltage VIH 2.0 - - V

Input Low Current IIL VIN=0V -15.0 -6.0 µA

Input High Current IIH VIN=VDD -2.0 - 2.0 µA

Pull-up Resistor, Note 1 Rpu VIN=VDD-1V - 400 700 k ohms

Output Low Current, Note 1 IOL VOUT=0. 8V 25 45 - mA

Output High Current, Note 1 IOH VOUT=2.0V - -53 -35 mA

Output Low Voltage VOL IOL=10mA - 0.15 0.4 V

Output High Voltage, Note 1 VOH IOH=-30mA 2.4 3.7 - V

Supply Current IDD No load, at 50 MHz - 18 35 mA

Output Frequency Change over

Supply and Temperature, Note 1 FdWith respect to typical

frequency - 0.002 0.05 %

Standby Supply Current, Note 2 IDDSTDBY Unloaded - 12 25 mA

ICS9131

Electrical Characteristics at 5V

Operating VDD = +4.5V to +5.5V; TA =0°C to 70°C unless otherwise stated

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

Note 2: With the STOPCLK pin low (active).

Note 3: Absolute Jitter measured as the shortest and longest period difference to the mean period of the sample set.

AC Characteristics

PARAM ETER SYMBOL TEST CONDITIONS MIN TYP MAX UNITS

Output Frequency, Note 1 foClock1 12.0 - 100 MHz

Input Frequency, Note 1 fi2.0 32 38 kHz

Output Rise time, Note 1 tr15pF load, 0.8 to 2.0V - 0.60 1.4 ns

Rise time, Note 1 tr15pF load, 20% to 80% VDD - 1.6 3.0 ns

Output Fall time, Note 1 tf15pF load, 2.0 to 0.8V - 0.50 1.2 ns

Fall time, Note 1 tf15pF load, 80% to 20% VDD - 0.9 2.5 ns

Duty cycle, Note 1 dt15pF load @1.4V 45 50 55 %

Jitter, 1 sigma from 33-80 MHz,

Note 1 Tjis 10,000 samples - 50 150 ps

Jitter, Absolute from 33-80 MHz,

Notes 1, 3 Tjabs 10,000 samples -250 - 250 ps

Jitter, 1 sigma from 16-25 MHz,

Note 1 Tjis 10,000 samples 60 150 ps

Jitter, Absolute from 16-25 MHz,

Note 1, 3 Tjabs 10,000 samples -600 - 600 ps

Jitter, 1 sigma from 14 to below,

Note 1 Tjis 10,000 samples - 1 3 %

Jitter, Absolute from 14 to below,

Note 1, 3 Tjabs 10,000 samples - 2 5 %

Frequency Transition time, Note 1 tft 2.0 5.0 10.0 ms

Power-up time, Note 1 tpu 3.0 7.5 15 ms

ICS9131

Electrical Characteristics at 3.3V

Operating VDD = +3.3V to +3.7V; TA =0°C to 70°C unless otherwise stated

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

Note 2: With the STOPCLK pin low (active).

Note 3: Absolute Jitter measured as the shortest and longest period difference to the mean period of the sample set.

DC Characteristics

PARAMETER SYMBOL TEST CONDITIONS MIN TYP MAX UNITS

Input Low Voltage VIL - - 0.2 VDD V

Input High Voltage VIH 0.7 VDD --V

Input Low Current IIL VIN=0V -7.0 -2.5 µA

Input High Current IIH VIN=VDD -2.0 - 2.0 µA

Pull-up Resistor, Note 1 Rpu VIN=VDD-1V - 600 900 k ohms

Output Low Current, Note 1 IOL VOUT=0.2V 15 24 - mA

Output High Current, Note 1 IOH VOUT=0.7V - -13 -8 mA

Output Low Voltage, Note 1 VOL IOL=60mA - 0.05 V DD 0.1 V DD V

Output High Voltage, Note 1 VOH IOH=-4.0mA 6.85 V DD 0.94 V DD -V

Supply Current IDD No load, at 50 MHz - 13 25 mA

Output Frequency Change over

Supply and Temperature, Note 1 FdWith respect to typical

frequency - 0.002 0.05 %

Standby Supply Current, Note 2 IDDSTDBY No load - 8 15 mA

AC Characteristics

Output Frequency, Note 1 foClock1 12.0 - 100 MHz

Input Frequency, Note 1 fi2.0 32 38 kHz

Rise time, Note 1 tr15pF load, 20% to 80% VDD - 2.2 3.5 ns

Fall time, Note 1 tf15pF load, 80% to 20% VDD - 1.2 2.5 ns

Duty cycle, Note 1 dt15pF load @50% V DD 43 - 53 %

Jitter, 1 sigma , Note 1 Tjis 10,000 samples - 50 150 ps

Jitter, Absolute, Note 1, 3 Tjabs 10,000 samples -250 250 ps

Jitter, 1 sigma from 16-25 MHz Tjis 10,000 samples - 60 150 ps

Jitter, Absolute from 16-25 MHz Tjabs 10,000 samples -600 - 600 ps

Jitter, 1 sigma from 14 to below Tjis 10,000 samples - 1 3 %

Jitter, Absolute from 14 to below Tjabs 10,000 samples - 2 5 %

Frequency Transition time, Note 1 tft 6.7 14.0 ms

Power-up time, Note 1 tpu - 8.55 17.0 ms

ICS9131

Stop Clock Feature

The ICS9131 incorporates a unique stop clock feature

compat-ible with static logic processors. When the stop

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

occuring 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 Star motherboard

applications.

32 kHz Supply Current

ADVANCE INFORMATION 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.

ICS9131

Ordering Information

ICS9131-01CN16 or ICS9131-01CS16

Example:

ICS XXXX M X#W

16-Pin SOIC P acka ge

Lead Count & Package Width

Lead Count=1, 2 or 3 digits

W=.3” SOIC or .6” DIP; None=Standard Width

Package Type

N=DIP (Plastic)

S=SOIC

Device Type (consists of 3 or 4 digit numbers)

Prefix

ICS, A V=Standard Device

16-Pin DIP Pack age