MK3233

Handheld System Clock Synthesizer

MDS 3233 F

2

Revision 11070

Printed 11/16/00

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

I C R O

Pin Assignment

Number

Name

Type

Description

1

CPUS2

I

Select 2 for CPUCLK frequencies. See Table above.

2

X2

O

Crystal connection. Connect to 32.768 kHz crystal.

3

X1

I

Crystal connection. Connect to 32.768 kHz crystal.

4

VDD32

P

Separate power supply connection for 32.768 kHz clock. Will operate to 2.0 V.

5

VDD

P

Connect to +3.3 V or +5 V. Must be the same voltage as pin 13.

6

GND

P

Connect to ground.

7

COMMCLK

O

Serial communications (1.84 on -01 version, or 3.68MHz on -02 version) clock output.

8

32K

O

32.768 kHz square wave clock output.

9

PDCOMM

I

Power Down serial Communications clock output (stops low) when low.

10

PDCPU

I

Power Down CPU clock output (stops low) when low.

11

PD

I

Powers Down everything but 32 kHz oscillator internally. 32 kHz output buffer is off.

12

GND

P

Connect to ground.

13

VDD

P

Connect to +3.3 V or +5 V. Must be the same voltage as pin 5.

14

CPUCLK

O

CPUCLK output. See Table above.

15

CPUS0

I

Select 0 for CPUCLK frequencies. See Table above.

16

CPUS1

I

Select 1 for CPUCLK frequencies. See Table above.

Pin Descriptions

CPUS2 CPUS1 CPUS0 CPUCLK (MHz)

0

0

0

8.00

0

0

1

13.00

0

1

0

16.00

0

1

1

20.00

1

0

0

40.00

1

0

1

25.00

1

1

0

50.00

1

1

1

33.33

CPU Clock Decoding

Type: I = Input, O = output, P = power supply connection

Power Down status: Output clocks will stop in a low state when powered down

1

8

9

16

2

3

4

5

6

7

10

11

12

13

14

15

CPUS1

PDCOMM

PDCPU

CPUCLK

PD

CPUS0

VDD

GND

CPUS2

32K

X2

GND

COMMCLK

VDD32

VDD

X1

External Components

The MK3233 requires a minimum number of external components for proper operation. Decoupling

capacitors of 0.1µF should be connected between VDD and GND, and VDD32 and GND, as close to the

MK3233 as possible. A series resistor should be used on the VDD32 supply. A series termination resistor of

33

Ω may be used for each clock output, except the 32.768 kHz. For tuning the real time clock output, use

a 32.768 kHz crystal with a load capacitance of 12.5pF, and connect a 20pF±5% (NPO dielectric)

capacitor between each crystal pin and ground. The 32.768 kHz crystal must be connected as close to the

chip as possible. Consult MicroClock for a recommended external circuit schematic.

Frequency transitions will occur smoothly.