MK1442-02S - Integrated Circuit Systems, Inc.

MK1442/MK1443

SCSI and Ethernet Clock Source

MDS 1442/3 E 1Revision 111500 Printed 11/15/00

Integrated Circuit Systems, Inc. • 525 Race Street • San Jose • CA • 95126 •(408)297-1201tel • www.icst.com

The MK1442/3 are the ideal way to generate

clocks for desktop computer motherboards and

LAN workstations. Using analog Phase-Locked

Loop (PLL) techniques, the devices accept a

14.318 MHz crystal input to produce multiple

output clocks up to 100 MHz. They provide

2XCPU, CPU, floppy controller, keyboard,

system, SCSI and Ethernet clocks. The MK1442/3

are perfect for new Pentium™ Processor, PCI bus

and 486 systems. The devices can operate at 5V or

3.3V up to and including 80MHz on the CPU

clock.

The devices are identical except the MK1442 has

an Output Enable (OE) pin that tri-states all

outputs when taken low, and the MK1443 has an

extra 14.318 MHz clock.

Crystal

Oscillator

VDD GND

Clock Synthesis

and Control

Circuitry

2XCPU

14.318 MHz

40.000 MHz

24.00 MHz

8.00, 12.00,

or 16.00 MHz

Output

Buffer

CPUS0

CPUS1

14.318 MHz

crystal

Block Diagram

Description Features

Output

Buffer

Output

Buffer

Output

Buffer

Output

Buffer

Output

Buffer

Output

Buffer

÷2 CPU

OE (all outputs, MK1442 only)

20.000 MHz

• Provides exact frequency Ethernet and SCSI clocks

• 5V or 3.3V (up to 80MHz) operation

• Output clock frequencies up to 100 MHz

• Pentium™ Processor compatible timing

• 486 compatible smooth frequency transitions

• Seven or eight output clocks

• Compatible with X86 and 680X0 CPUs

• Skew controlled 2X and 1X CPU to within 250ps

• Packaged in 16 pin skinny SOIC or PDIP

• Duty cycle of 47.5/52.5 up to 66.66 MHz

• Duty cycle of 45/55 up to 100 MHz

• Total of 15 different selectable CPU frequencies

• Tri-state outputs for board level testing

• 25mA drive capability at TTL levels

• Keyboard frequencies of 12MHz (-01),

8MHz (-02), or 16MHz (-03)

• Advanced, low power CMOS process

• MK1442 - output enable

• MK1443 - two 14.318 MHz outputs

14.318 MHz

(MK1443 only)

Output

Buffer

MK1442/MK1443

SCSI and Ethernet Clock Source

MDS 1442/3 E 2Revision 111500 Printed 11/15/00

Integrated Circuit Systems, Inc. • 525 Race Street • San Jose • CA • 95126 •(408)297-1201tel • www.icst.com

Number Name Type Description

1CPUS1 TI Select 1 for 2XCPU and CPU frequencies. See Table above, note 5 below.

2X2 O Crystal connection. Connect to 14.318 MHz crystal, or leave unconnected for clock input.

3X1 I Crystal connection. Connect to 14.318 MHz crystal, or drive with a 14.318MHz clock.

4 VDD P Connect to +5V or 3.3V. Must be same voltage as pin 13.

5GND P Connect to ground.

6 24M O 24.00 MHz floppy (or super I/O) clock output.

7 40M O 40.00 MHz clock output

8 20M O 20.000 MHz Ethernet clock output

9KBOUT O Keyboard clock. 12.00 MHz on -01, 8.00 MHz on -02, 16.00 MHz on -03 version.

10 OE I Output Enable on 1442. Tri-states all clock outputs when this input is low. Internal pull-up.

11 14.3M O 14.318 MHz system clock output.

12 GND P Connect to ground.

13 VDD P Connect to +5V or 3.3V. Must be same voltage as pin 4.

14 CPU O CPU output. See Table above. Rising edge is within 250ps of 2XCPU.

15 2XCPU O 2XCPU output. See Table above. Rising edge is within 250ps of CPU.

16 CPUS0 TI Select 0 for 2XCPU and CPU frequencies. See Table above, note 5 below.

Pin Descriptions

CPUS1 CPUS0 2XCPU (MHz) CPU (MHz)

0 0 8.00 4.00

0 M 80.00 40.00

0 1 33.33 16.67

M 0 100.00 (note 4) 50.00 (note 4)

M M 66.67 33.33

M 1 60.00 30.00

1 0 50.00 25.00

1 M 20.00 10.00

1 1 25.00 12.50

CPU Clock Decoding

Notes:

1. M = mid point (input is left floating. See note 5 below)

2. Actual frequencies are within 0.05% of those shown.

3. Transitions between mean frequencies are smooth, and do not

violate Intel’s 0.1% per cycle specification.

4. These selections are not guaranteed to operate at 3V

Key: I = Input, TI = three level input, O = output, P = power supply connection

Note 5: The TI inputs are internally held at mid-level, so they cannot drift high or low.

8 9

7 10

15 CPUS0

14.3M

CPU

2XCPU

VDD

GND

CPUS1

40M

24M

VDD

GND

20M KBOUT

OE or 14.3M

(MK1442) (MK1443)

Pin Assignment

Crystal and Capacitor Selection for Ethernet Accuracy

The MK1442/3 requires external crystals between the X1 and X2 pins and ground, as shown on the block

diagram on page 1. For an accurate Ethernet frequency of 20.000 MHz, a 14.31818 MHz ±50 ppm,

parallel resonant crystal with a load capacitance of 16pF is recommended, along with 22 pF ±5% (NPO

dielectric) chip capacitors. If the 20 MHz output is not used for Ethernet, any 22 pF capacitors will work.

MK1442/MK1443

SCSI and Ethernet Clock Source

MDS 1442/3 E 3Revision 111500 Printed 11/15/00

Integrated Circuit Systems, Inc. • 525 Race Street • San Jose • CA • 95126 •(408)297-1201tel • www.icst.com

Parameter Conditions Minimum Typical Maximum Units

ABSOLUTE MAXIMUM RATINGS (note 1)

Supply voltage, VDD Referenced to GND 7 V

Inputs and Clock Outputs Referenced to GND -0.5 VDD+0.5 V

Ambient Operating Temperature 0 70 °C

Soldering Temperature Max of 20 seconds 260 °C

Storage Temperature -65 150 °C

DC CHARACTERISTICS (VDD = 5V unless noted)

Operating Voltage, VDD 3.0 5.5 V

Input High Voltage, VIH OE (pin 10) 2.0 V

Input Low Voltage, VIL OE (pin 10) 0.8 V

Input High Voltage, VIH CPUS0,1 (pins 1,16) VDD-0.5 V

Input Mid-level Voltage CPUS0,1 (pins 1,16)

Leave pin unconnected or tri-stated

Input Low Voltage, VIL CPUS0,1 (pins 1,16) 0.5 V

Output High Voltage, VOH IOH=-4mA VDD-0.4 V

Output High Voltage, VOH IOH=-25mA 2.4 V

Output Low Voltage, VOL IOL=25mA 0.4 V

Input High Voltage, VIH VDD=3.3V, OE pin 1.9 V

Input Low Voltage, VIL VDD=3.3V, OE pin 0.4 V

Output High Voltage, VOH VDD=3.3V, IOH=-8mA 2.4 V

Output Low Voltage, VOL VDD=3.3V, IOL=8mA 0.4 V

Operating Supply Current, IDD No Load, 80 MHz 35 mA

Short Circuit Current Each output ±100 mA

On-Chip Pull-up Resistor 250 kΩ

Input Capacitance 7 pF

Frequency Accuracy of 20.000 MHz clock 0-70°C, note 2 -1 1 ppm

AC CHARACTERISTICS (VDD = 5V unless noted)

Input Frequency 14.31818 MHz

Output Clock Rise Time 0.8 to 2.0V 1.5 ns

Output Clock Fall Time 2.0 to 0.8V 1.5 ns

Output Clock Duty Cycle, CPU and 2XCPU 1.5V, up to 67MHz 47.5 49 to 51 52.5 %

Output Clock Duty Cycle At 1.5V 45 49 to 51 55 %

Cycle to Cycle Jitter 50-80 MHz clocks 250 ps

Skew of 2XCPU with respect to CPU Rising edges at 1.5V -250 0 250 ps

Transition time, 8MHz to 100MHz VDD=3.3 or 5V 4 ms

Transition time, 100MHz to 8MHz VDD=3.3 or 5V 2.5 ms

Output Enable Time, OE high to output on VDD=3.3 or 5V 50 ns

Output Disable Time, OE low to tri-state VDD=3.3 or 5V 3 µs

Electrical Specifications

Notes: 1. Stresses beyond those listed under Absolute Maximum Ratings could cause permanent damage to the device. Prolonged

exposure to levels above the operating limits but below the Absolute Maximums may affect device reliability.

2. Provided proper crystal and capacitor components are used - consult MicroClock.

MK1442/MK1443

SCSI and Ethernet Clock Source

MDS 1442/3 E 4Revision 111500 Printed 11/15/00

Integrated Circuit Systems, Inc. • 525 Race Street • San Jose • CA • 95126 •(408)297-1201tel • www.icst.com

While the information presented herein has been checked for both accuracy and reliability, MicroClock Incorporated assumes no responsibility for either its use or for the

infringement of any patents or other rights of third parties, which would result from its use. No other circuits, patents, or licenses are implied. This product is intended for use in

normal commercial applications. Any other applications such as those requiring extended temperature range, high reliability, or other extraordinary environmental requirements

are not recommended without additional processing by MicroClock. MicroClock reserves the right to change any circuitry or specifications without notice. MicroClock does not

authorize or warrant any MicroClock product for use in life support devices or critical medical instruments.

Pentium™ is a registered trademark of Intel Corporation

E H

QcA

h x 45°

Package Outline and Package Dimensions

Ordering Information

Part/Order Number Marking Keyboard frequency Package Temperature

MK1442-01S MK1442-01S 12 MHz 16 pin SOIC 0-70°C

MK1442-02S MK1442-02S 8 MHz 16 pin SOIC 0-70°C

MK1442-03S MK1442-03S 16 MHz 16 pin SOIC 0-70°C

MK1443-01S MK1443-01S 12 MHz 16 pin SOIC 0-70°C

MK1443-02S MK1443-02S 8 MHz 16 pin SOIC 0-70°C

MK1443-03S MK1443-03S 16 MHz 16 pin SOIC 0-70°C

MK144x-0xSTR MK144x-0xS x Add Tape & Reel 0-70°C

16 pin SOIC narrow

Inches

Millimeters

Symbol Min Max Min Max

A0.055 0.070 1.397 1.778

b 0.013 0.019 0.330 0.483

c 0.007 0.010 0.191 0.254

D 0.385 0.400 9.779 10.160

E 0.150 0.160 3.810 4.064

H 0.225 0.245 5.715 6.223

.050 BSC

1.27 BSC

h 0.016 0.406

Q 0.004 0.01 0.102 0.254