MK2745-21
DVD/MPEG Clock Source
Description
The MK2745-21 is a low cost, low jitter, high
performance clock synthesizer for DVD and other
MPEG 2 based applications. Using analog Phase-
Locked Loop (PLL) techniques, the device accepts
a 27.00MHz fundamental mode crystal or clock
input to produce multiple output clocks including
the processor clock, the processor clock divided by
two, 27 MHz, 24.576 MHz, and a selectable
audio clock. The audio clocks are frequency
locked to the 27.00MHz input 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.
Features
• Packaged in 16 pin narrow (150 mil) SOIC
• Ideal for LuxSonor’s DVD solutions
• 3.3V upgrade to MK2744
• Patented zero ppm audio clock error for 256X and
384X sampling rates
• Selectable audio sampling frequencies support
32 kHz, 44.1 kHz, and 48 kHz in most DACs
• 27.00 MHz fundamental crystal or clock input
• Eight selectable processor frequencies
• Fixed clocks of 27 and 24.576 MHz
• Zero ppm error in all clocks
• Full CMOS outputs with 25mA output drive
capability at TTL levels
• Advanced, low power, sub-micron CMOS process
• 3.0V to 5.5V operating voltage
• See also the MK2712 for NTSC/PAL clocks
Block Diagram
VDD
GND
2
AS2:0
3
2
Output
Buffer
Audio Clock
24.576 MHz
Processor Clock
PCLK/2
27 MHz
PS1:0
27.00 MHz
clock or
crystal
X1
2
Clock Synthesis
and Control
Circuitry
Output
Buffer
Output
Buffer
÷2
Output
Buffer
Output
Buffer
X2
Clock
Buffer/
Crystal
Oscillator
MDS 2745-21 B
1
Revision 120400
Printed 12/5/00
Integrated Circuit Systems, Inc.•525 Race Street•San Jose•CA•95126•(408)295-9800tel•www.icst.com
MK2745-21
DVD/MPEG Clock Source
Pin Assignment
MK2745-21
PS1
X2
X1/ICLK
VDD
GND
ACLK
PCLK
AS2
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
PS0
24.576M
PCLK/2
VDD
AS1
GND
27M
AS0
Audio Clock (in MHz)
Decoding Table
AS2 AS1 AS0
0
0
0
0
0
1
0
1
0
0
1
1
1
0
0
1
0
1
1
1
0
1
1
1
ACLK
12.288
11.2896
8.192
24.576
8.192
16.9344
18.432
11.2896
Processor Clock (in MHz)
PS1
0
0
1
1
PS0
0
1
0
1
PCLK
66.66
80
50
60
PCLK/2
33.33
40
25
30
0 = connect directly to ground
1 = connect directly to VDD
16 pin (150 mil) SOIC
Pin Descriptions
Number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Name
PS1
X2
X1/ICLK
VDD
GND
ACLK
PCLK
AS2
AS0
27M
GND
AS1
VDD
PCLK/2
24.576M
PS0
Type
I
XO
XI
P
P
O
O
I
I
O
P
I
P
O
O
I
Description
Processor clock Select 1. Selects processor clock outputs per table above.
Crystal connection. Connect to 27 MHz crystal. Leave unconnected for clock input.
Crystal connection. Connect to 27 MHz crystal or connect to 27 MHz input clock.
Connect to +3.3 V or +5 V. Must be same as other VDD.
Connect to ground.
Audio Clock output. Determined by status of AS2, AS1, AS0. See table above.
Processor Clock output. Determined by status of PS1, PS0. See table above.
Audio clock Select 2. Selects audio clock on pin 6 per table above.
Audio clock Select 0. Selects audio clock on pin 6 per table above.
27.00 MHz clock output.
Connect to ground.
Audio clock Select 1. Selects audio clock on pin 6 per table above.
Connect to +3.3 V or +5 V. Must be same as other VDD.
Processor Clock divided by two output. Determined by status of PS1, PS0. See table above.
24.576 MHz clock output.
Processor clock Select 0. Selects processor clock outputs per table above.
Key: I = Input, O = output, P = power supply connection
MDS 2745-21 B
2
Revision 120400
Printed 12/5/00
Integrated Circuit Systems, Inc.•525 Race Street•San Jose•CA•95126•(408)295-9800tel•www.icst.com
MK2745-21
DVD/MPEG Clock Source
Electrical Specifications
Parameter
Supply voltage, VDD
Inputs and Clock Outputs
Ambient Operating Temperature
Soldering Temperature
Storage temperature
Operating Voltage, VDD
Input High Voltage, VIH, X1/ICLK pin only
Input Low Voltage, VIL, X1/ICLK pin only
Input High Voltage, VIH
Input Low Voltage, VIL
Output High Voltage, VOH
Output Low Voltage, VOL
Output High Voltage, VOH, CMOS level
Operating Supply Current, IDD
Short Circuit Current
Input Capacitance
Input Frequency
Output Clock Rise Time
Output Clock Fall Time
Output Clock Duty Cycle
Frequency error, all clocks
Absolute Jitter, short term
Notes:
Conditions
Referenced to GND
Referenced to GND
Max of 20 seconds
-65
3
VDD/2 + 1
2
0.8
IOH=-25mA
IOL=25mA
IOH=-8mA
No Load, note 2
Each output
2.4
0.4
VDD-0.4
37
±100
7
27.000
0.8 to 2.0V
2.0 to 0.8V
At VDD/2
Variation from mean
1.5
1.5
60
1
Minimum
Typical
Maximum
7
VDD+0.5
70
260
150
5.5
VDD/2
VDD/2
VDD/2 - 1
Units
V
V
°C
°C
°C
V
V
V
V
V
V
V
V
mA
mA
pF
MHz
ns
ns
%
ppm
ps
ABSOLUTE MAXIMUM RATINGS (note 1)
-0.5
0
DC CHARACTERISTICS (VDD = 5.0V unless noted)
AC CHARACTERISTICS (VDD = 5.0V unless noted)
40
0
200
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. With Processor clock at 50MHz, and ACLK at 16.93MHz.
External Components
The MK2745-21 requires a minimum number of external components for proper operation. Decoupling
capacitors of 0.1µF should be connected between VDD and GND, as close to the MK2745-21 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 C
L
is the crystal load capacitance: Crystal caps (pF) = (C
L
-6) x 2. So for a crystal
with 16pF load capacitance, two 20pF caps should be used.
MDS 2745-21 B
3
Revision 120400
Printed 12/5/00
Integrated Circuit Systems, Inc.•525 Race Street•San Jose•CA•95126•(408)295-9800tel•www.icst.com
MK2745-21
DVD/MPEG Clock Source
Package Outline and Package Dimensions
16 pin SOIC narrow
Symbol
A
b
c
D
E
H
e
h
Q
Inches
Min
Max
0.055 0.070
0.013 0.019
0.007 0.010
0.385 0.400
0.150 0.160
0.225 0.245
.050 BSC
0.016
0.004
0.01
Millimeters
Min
Max
1.397
1.778
0.330
0.483
0.191
0.254
9.779 10.160
3.810
4.064
5.715
6.223
1.27 BSC
0.406
0.102
0.254
E
H
D
Q
e
b
c
h x 45°
A
Ordering Information
Part/Order Number
MK2745-21S
MK2745-21STR
Marking
MK2745-21S
MK2745-21S
Shipping packaging
tubes
tape and reel
Package
Temperature
16 pin narrow SOIC
0-70°C
16 pin narrow SOIC
0-70°C
Rev. 03318, version A . First publication, Preliminary.
Rev. 04218, version B. Corrected VDD, VIH/VIL under DC Characteristics. Preliminary.
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.
MDS 2745-21 B
4
Revision 120400
Printed 12/5/00
Integrated Circuit Systems, Inc.•525 Race Street•San Jose•CA•95126•(408)295-9800tel•www.icst.com
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