Datasheet MK2745-24S, MK2745-24STR Datasheet (ICST)

MK2745-24

ICRO

C

LOCK

Description

The MK2745-24 is a low cost, low jitter, high
performance clock synthesizer for DVD and other
MPEG 2 based applications. Using analog Phase­Locked Loop (PLL) techniques, the device accepts
a 27.00 MHz fundamental mode crystal or clock
input to produce multiple audio output clocks, a
processor clock, and two 27 MHz clocks. The
audio clocks are frequency locked to the

27.00 MHz using our patented zero ppm error
techniques, allowing audio and video to track
exactly, thereby eliminating the need for large
buffer memory.

MicroClock manufactures the largest variety of
DVD, Set-Top Box, and multimedia clock
synthesizers for all applications. Consult
MicroClock to eliminate crystals and oscillators
from your board.

DVD/MPEG Clock Source

Features

• Packaged in 16 pin narrow (150 mil) SOIC

• Ideal for AuraVision’s notebook DVD solutions

• Patented zero ppm audio clock error for exact
audio clock sampling rates, plus 32x and 256x
clocks of the sampling frequencies

• Selectable audio sampling frequencies support
32, 44.1, 48 and 96 kHz in most DACs

• 27.00 MHz fundamental crystal or clock input

• Selectable processor frequencies

• Two clocks of 27 MHz

• Zero ppm error in all clocks

• 25mA output drive capability at TTL levels

• Advanced, low power, sub-micron CMOS process

• 3.0V to 5.5V operating voltage

Block Diagram

ACS1:0

PCS

27 MHz clock
or crystal

X1

X2

VDD GND

2 3

2

/

Clock Synthesis

and Control

Crystal

Oscillator

Circuitry

• See also the MK2712 for NTSC/PAL clocks

÷8

÷256

Output

Buffer

Output

Buffer

Output

Buffer

Output

Buffer

Output

Buffer

Output

Buffer

PCLK

ACLK

ACLK/8

ACLK/256

27.0 MHz

27.0 MHz

MDS 2745-24 B 1 Revision 100898 Printed 11/16/00

MicroClock Division of ICS•1271 Parkmoor Ave.•San Jose•CA•95126•[phone]tel•[phone]fax

MK2745-24

ICRO

Pin Assignment

MK2745-24

GND ACS1

X2

X1/ICLK

VDD

GND

27M

ACS0

ACLK/8

1

2

3
4

5

6
7
8

16 pin (150 mil) SOIC

16
15

14
13

12

11

10

9

C

LOCK

27M
PCLK

VDD
GND

ACLK

PCS
ACLK/256

DVD/MPEG Clock Source

Audio Clocks Selection Table (in MHz)

ACS1 ACS0 ACLK ACLK/8 ACLK/256

0 0 24.576 3.072 96.0 kHz
0 1 11.2896 1.4112 44.1 kHz
1 0 8.192 1.024 32.0 kHz
1 1 12.288 1.536 48.0 kHz

Processor Clock (MHz)

PCS PCLK

0 40
1 60

0 = connect directly to ground
1 = connect directly to VDD

Pin Descriptions

Number Name Type Description

1 GND P Connect to ground.
2 X2 XO Crystal connection. Connect to 27 MHz crystal. Leave unconnected for clock input.
3 X1/ICLK XI Crystal connection. Connect to 27 MHz crystal or connect to 27 MHz input clock.
4 VDD P Connect to +3.3 V or +5 V. Must be same as other VDD.
5 GND P Connect to ground.
6 27M O 27.00 MHz clock output.
7 ACS0 I Audio Clock Select 0. Selects audio clocks per table above.
8 ACLK/8 O Audio Clock divided by 8 output. Determined by status of ACS1, ACS0. See table above.

9 ACLK/256 O Audio Clock divided by 256 output. Determined by status of ACS1, ACS0. See table above.
10 PCS I Processor Clock Select pin. Selects PCLK per table above.
11 ACLK O Audio Clock output. Determined by status of ACS1, ACS0. See table above.
12 GND P Connect to ground.
13 VDD P Connect to +3.3 V or +5 V. Must be same as other VDD.
14 PCLK O Processor Clock output. Determined by status of PCS. See table above.
15 27M O 27.00 MHz clock output.
16 ACS1 I Audio Clock Select 1. Selects audio clocks per table above.

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

MDS 2745-24 B 2 Revision 100898 Printed 11/16/00

MicroClock Division of ICS•1271 Parkmoor Ave.•San Jose•CA•95126•[phone]tel•[phone]fax

MK2745-24

ABSOLUTE MAXIMUM RATINGS (note 1)

DC CHARACTERISTICS (VDD = 5.0V unless noted)

AC CHARACTERISTICS (VDD = 5.0V unless noted)

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

2. With VDD=3.3V, processor clock at 60MHz, and ACLK at 12.288MHz.

ICRO

C

LOCK

DVD/MPEG Clock Source

Electrical Specifications

Parameter Conditions Minimum Typical Maximum Units

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

Operating Voltage, VDD 3 5.5 V
Input High Voltage, VIH, X1/ICLK pin only VDD/2 + 1 VDD/2 V
Input Low Voltage, VIL, X1/ICLK pin only VDD/2 VDD/2 - 1 V
Input High Voltage, VIH 2 V
Input Low Voltage, VIL 0.8 V
Output High Voltage, VOH IOH=-25mA 2.4 V
Output Low Voltage, VOL IOL=25mA 0.4 V
Output High Voltage, VOH, CMOS level IOH=-8mA VDD-0.4 V
Operating Supply Current, IDD No Load, note 2 37 mA
Short Circuit Current Each output ±100 mA
Input Capacitance 7 pF

Input Frequency 27.000 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 At VDD/2 40 60 %
Frequency synthesis error, all clocks 0 1 ppm
Absolute Jitter, short term Variation from mean 200 ps

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

External Components

The MK2745-24 requires a minimum number of external components for proper operation. Decoupling
capacitors of 0.1µF should be connected between VDD and GND (on pins 4 and 5, and pins 13 and 12),
as close to the MK2745-24 as possible. A series termination resistor of 33Ω may be used for each clock
output. If a clock input is not used, the 27.00 MHz crystal must be connected as close to the chip as
possible. The crystal should be a fundamental mode (do not use third overtone), parallel resonant, 50ppm
or better. Crystal capacitors should be connected from pins X1 to ground and X2 to ground. The value of
these capacitors is given by the following equation, where CL is the crystal load capacitance: Crystal caps

(pF) = (CL-6) x 2. So for a crystal with 16pF load capacitance, two 20pF caps should be used.

MDS 2745-24 B 3 Revision 100898 Printed 11/16/00

MicroClock Division of ICS•1271 Parkmoor Ave.•San Jose•CA•95126•[phone]tel•[phone]fax

MK2745-24

Inches

Millimeters

ICRO

C

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Package Outline and Package Dimensions

E H

h x 45°

D

Q

e

b

c

DVD/MPEG Clock Source

16 pin SOIC narrow

Symbol Min Max Min Max

A 0.055 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

e

h 0.016 0.406

Q 0.004 0.01 0.102 0.254

A

Ordering Information

Part/Order Number Marking Shipping packaging Package Temperature

MK2745-24S MK2745-24S tubes 16 pin narrow SOIC 0-70°C

MK2745-24STR MK2745-24S tape and reel 16 pin narrow SOIC 0-70°C

Rev. 04218, version A . First publication, Preliminary.
Rev. 10088, version B. Production.

While the information presented herein has been checked for both accuracy and reliability, Integrated Circuit Systems, Incorporated (ICS) 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 ICS. ICS reserves the right to change any circuitry or specifications without notice. ICS does
not authorize or warrant any ICS product for use in life support devices or critical medical instruments.

MDS 2745-24 B 4 Revision 100898 Printed 11/16/00

MicroClock Division of ICS•1271 Parkmoor Ave.•San Jose•CA•95126•[phone]tel•[phone]fax