Integrated
Circuit
Systems, Inc.

General Description

Features

ICS9133X

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.

The ICS9133X is designed to generate clocks for all 286, 386,
486, Pentium and RISC-based motherboards, including lap-
tops and notebook computers. The only external components
required are a 32.768 kHz crystal and decoupling capacitors.
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. The
chip includes three independent clock generators plus the
32.768 kHz reference clock to produce all necessary frequencies,
including real time clock/DRAM refresh, master clock, CPU
clock, twice CPUclock frequency, keyboard clock, floppy
disk controller clock, serial communications clock and bus
clocks. Different frequencies from clock #2 can be selected
using the frequency select pins, but clock #1 will be at 14.318
MHz for all standard versions.

Single 32.768 kHz crystal generates all PC
motherboard clocks

Cost-reduced version of popular ICS9132

Contains internal crystal load capacitors and
feedback bias

3 independent clock generators

Generates CPU clocks from 12.5 to 100 MHz

Up to 7 output clocks

Separate VDD for 32 kHz clock

Output enable tristates outputs

Power-down options available

Operates from 3.3V or 5.0V supply

Operates up to 66 MHz at 3.3V

Skew controlled 1X and 2X CPU clocks

20-pin PDIP or SOIC package

9133X Rev A 052897P

Block Diagram

32 kHz Motherboard Frequency Generator

VDD32 Supply

The ICS9133X 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 with the main VDD at 0V.

The frequencies and power-down options in the ICS9133X
are mask programmable. Customer specific masks can be
made and prototypes delivered within 6-8 weeks from receipt
of order. Integrated Circuit Systems also offers standard versions,
such as that described in this data sheet.

Applications

Notebook/Palmtop Computers: The ICS9133X works with
+3V and +5V and a single 32.768 kHz crystal, making it the
ideal solution for generating clocks in portables with minimum
board space. The user can save power by using this single part
instead of oscillators or other frequency generators. The
ICS9133X further reduces the current consumption by having
the ability to completely shut down the individual clocks
when not in use, while still maintaining the separately powered
32.768 kHz clock.

ICS9133X

Pin Configuration

Decoding Table for CPU Clock

Pin Descriptions

* Only at 5V supply voltage

20-Pin PDIP or SOIC

PIN

NUMBER

PIN NAME

TYPE

DESCRIPTION

32 kHz

Output

32.768 kHz buffered output, powered by VDD32.

Output

Connect 32.768 kHz crystal. Includes internal XTAL load capacitance.

Input

Connect 32.768 kHz crystal. This pin includes internal XTAL load capacitance and
feedback bias for a 32.768 kHz crystal.

VDD32

Power supply for 32 kHz oscillator only.

VDD

Power supply (+3.3 to +5.0V).

GND

GROUND.

16 MHz

Output

16 MHz clock output.

24 MHz

Output

24 MHz clock output.

12 MHz

Output

12 MHz clock output.

GND

GROUND.

Input

OE tristate outputs when low. Has internal pull-up.

VDD

Power supply (+3.3 to +5.0V).

14.318 MHz

Output

14.318 MHz clock output.

GND

GROUND.

VDD

Power supply (+3.3 to +5.0V).

2XCPU

Output

2XCPU clock output (see decoding table).

CPU

Output

CPU clock output (see decoding table).

SCLK2

Input

CPU clock frequency SELECT2. Has internal pull-up.

SCLK1

Input

CPU clock frequency SELECT1. Has internal pull-up.

SCLK0

Input

CPU clock frequency SELECT0. Has internal pull-up.

SCLK22

SCLK21

SCLK20

2XCPU

CPU

0
0
0
0
1
1
1
1

0
0
1
1
0
0
1
1

0
1
0
1
0
1
0
1

16
32
40
50

66.6

80*

100*

4
8

16
20
25

33.3

40*
50*

ICS9133X

Block Diagram for ICS9133X

Recommended External Circuit

Reference

Clock

32.768 kHz

crystal

32.768 kHz

14.318 MHz

Clock

Generator

Output

Buffers

CPU

16 MHz

12 MHz

24 MHz

CPU Clock

2XCPU

Peripheral

Clocks

Output

Buffers

Output

Buffers

Frequency Select

Notes:
1. The external components shown should be placed as close to the device as possible.
2. Pins 5 and 15 should be connected together externally. One decoupling capacitor may suffice for both pins.
3. May be part of system decoupling.
4. Crystal load capacitance and feedback bias contained internally on the X1, X2 pins.

0.1µF

2.2µF

0.1µF

(Note 3)

32.768

kHz

VDDX

(Note 4)

VDD

ICS9133X

Electrical Characteristics at 3.3V

Operating V

= +3.0V to 3.7V; T

=0°C to 70°C unless otherwise stated

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

2. 32 kHz output duty cycle is dependent on crystal used.

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.

DC Characteristics

PARAMETER

SYMBOL

TEST CONDITIONS

MIN

TYP

MAX

UNITS

Input Low Voltage

0.2V

Input High Voltage

0.7V

Input Low Current

=0V (Pull-up)

-12

µA

Input High Current

-2

µA

Output Low Voltage

=4mA

0.1

Output High Voltage

=-1mA

-.1V

Output High Current

=-4mA

Output High Current

=-8mA

2.4

Output Frequency Change
over Supply and
Temperature

With respect to typical
frequency

.005

0.05

Short Circuit Current

Each output clock

Supply Current

No load, 40 MHz

32 Supply Current

No load, V

32=3.7V

µA

32 Supply Voltage

=0 to 3.7V, 32 kHz output

operating

2.0

Pull-up Resistor Value

Rpu

620

k½

AC Characteristics

Input Clock Rise Time

ICr

µs

Input Clock Fall Time

ICf

µs

Output Rise Time

15pF load, 0.8 to 2.0V

1.5

Rise Time

15pF load, 20% to 80% V

2.5

Output Fall Time

15pF load, 2.0 to 0.8V

1.5

Fall Time

15pF load, 80% to 20% V

2.5

Duty Cycle

15pF load @ V

=1.4V

43/57

48/52

57/43

Duty Cycle, reference
clocks

15pF load @ 1.4V

40/60

43/57

60/40

Jitter, One Sigma

As compared with clock period.

Jitter, Absolute

jab

Input Frequency

32.768

kHz

Clock Skew between any
Clock #2 outputs

100

500

Power-up Time

From off to 40 MHz

1,000

ICS9133X

Electrical Characteristics at 5V

= +5.0V ±10%; T

=0°C to 70°C unless otherwise stated

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

2. 32 kHz output duty cycle is dependent on crystal used.

DC Characteristics

PARAMETER

SYMBOL

TEST CONDITIONS

MIN

TYP

MAX

UNITS

Input Low Voltage

0.2V

Input High Voltage

0.7V

Input Low Current

=0V (Pull-up)

-15

µA

Input High Current

-2

µA

Output Low Voltage

=4mA

0.1

Output High Voltage

=-1mA

-.1V

Output High Voltage

=-4mA

Output High Voltage

=-8mA

2.4

Output Frequency Change
over Supply and
Temperature

With respect to typical
frequency

.005

0.05

Short Circuit Current

Each output clock

Supply Current

No load, 40 MHz

32 Supply Current

No load, V

32=5.5V

7.5

µA

32 Supply Voltage

=0 to 5.5V, 32 kHz output

operating

2.0

Pull-up Resistor Value

380

k½

AC Characteristics

Input Clock Rise Time

ICr

µs

Input Clock Fall Time

ICf

µs

Output Rise Time

15pF load, 0.8 to 2.0V

1.5

Rise Time

15pF load, 20% to 80% V

Output Fall Time

15pF load, 2.0 to 0.8V

1.5

Fall Time

15pF load, 80% to 20% V

Duty Cycle

15pF load @ V

=1.4V

43/57

48/52

57/43

Duty Cycle, reference
clocks

15pF load @ 1.4V

40/60

43/57

60/40

Jitter, One Sigma

j1s

As compared with clock period.

Jitter, Absolute

jab

Input Frequency

32.768

kHz

Clock Skew between any
Clock #2 outputs

100

500

Power-up Time

From off to 40 MHz

Part Number ICS9133X