MK3235

Handheld System Clock Synthesizer

MDS 3235 D

1

Revision 092397

Printed 11/16/00

Integrated Circuit Systems, Inc.•525 Race Street•San Jose•CA•95126•(408)295-9800tel•www.icst.com

I C R O

• Input crystal frequency of 32.768 kHz

• Lowest power solution available

• Lowest profile clock solution where height is critical

• Three output clocks

• 3.3V or 5.0V operation

• Duty cycle of 45/55

• 14.3MHz or 14.3MHz+Comm clock power downs

• Separate battery supply pin for 32 kHz runs to 2V

• IDD less than 4µA when 32 kHz running

• Packaged in 16 pin narrow SOIC

The MK3235 is the smallest size, lowest power system

clock synthesizer available. It is the ideal way to

generate clocks for handheld computers, such as PDAs,

PICs, and other devices where low power is required.

Using analog Phase-Locked Loop (PLL) techniques,

the device operates from a single 32.768 kHz crystal to

produce the 32.768kHz, 14.318MHz, and serial

communications output clocks.

The device has three power down modes for the

14.3MHz, communications, and 32.768kHz clocks.

The MK3235 can save board space and cost even if it

only replaces the 32kHz oscillator circuitry and one

additional surface mount crystal or oscillator. The

extremely low IDD, the ease of surface mounting, and

the power down capability are added benefits in using

the part.

Description

Features

Crystal

Oscillator

VDD

GND

14.318MHz

Clock Synthesis

and Control

Circuitry

14.3 MHz

32.768 kHz

1.843 or

3.686 MHz

Output

Buffer

Output

Buffer

Output

Buffer

32.768 kHz

crystal

Block Diagram

VDD32

PDCOMM

PD14

PD

X1

X2

Communications

Clock Synthesis

and Control

Circuitry