techniques, the device uses a standard fundamental
mode, inexpensive 14.31818 MHz crystal to
produce two 24.576 MHz output clocks. The
device can also accept a clock input.
MK1449C
Sound Clock
Features
• Packaged as 8 pin SOIC
• For sound on computer motherboards
• Less than 1 ppm synthesis error
• Input crystal frequency of 14.31818 MHz
• Extremely low jitter - 50 ps one sigma
• Duty cycle of 45/55 up
• Operating voltages of 3.0 to 5.5 V
• Full CMOS level outputs with 25 mA drive
capability at TTL levels
• Ideal for oscillator replacement
• Advanced, low power CMOS process
Block Diagram
VDD GND
2
Output
Buffer
PLL
Clock
Synthesis
and Control
Circuitry
Crystal
Oscillator
X2
24.576 MHz
14.31818MHz
crystal
X1
or clock
Output
Buffer
24.576 MHz
1
Revision 060198
Printed 11/15/00
MicroClock Division of ICS•1271 Parkmoor Ave.•San Jose•CA•95126•(408)295-9800tel•(408)295-9818fax
MDS 1449C A
PRELIMINARY INFORMATION
I C R O
C
LOC K
MK1449C
Sound Clock
Pin Assignment
X1/ICLK
VDD
GND
24.6M
1
2
3
4
8
7
6
5
X2
DC
VDD
24.6M
Pin Descriptions
Number
1
2
3
4
5
6
7
8
Name
X1/ICLK
VDD
GND
24.6M
24.6M
VDD
DC
X2
Type
I
P
P
O
O
P
-
O
Description
Crystal connection or clock input. Connect to a 14.31818MHz parallel resonant crystal.
Connect to +3.3V or +5V.
Connect to ground.
24.576 MHz output clock.
24.576 MHz output clock.
Connect to +3.3V or +5V.
Don't Connect. Do not connect anything to this pin.
Crystal connection to a 14.31818 MHz crystal. Leave unconnected for clock input.
Key: I = Input, O = output, P = power supply connection
2
Revision 060198
Printed 11/15/00
MicroClock Division of ICS•1271 Parkmoor Ave.•San Jose•CA•95126•(408)295-9800tel•(408)295-9818fax
MDS 1449C A
PRELIMINARY INFORMATION
I C R O
C
LOC K
Electrical Specifications
Parameter
Conditions
Minimum
Typical
ABSOLUTE MAXIMUM RATINGS (stresses beyond these can permanently damage the device)
Supply Voltage, VDD
Referenced to GND
Inputs
Referenced to GND
-0.5
Clock Output
Referenced to GND
-0.5
Ambient Operating Temperature
0
Soldering Temperature
Max of 10 seconds
Storage temperature
-65
DC CHARACTERISTICS (VDD = 5.0V unless otherwise noted)
Operating Voltage, VDD
3
Input High Voltage, VIH, ICLK only
ICLK (Pin 1)
(VDD/2)+1
VDD/2
Input Low Voltage, VIL, ICLK only
ICLK (Pin 1)
VDD/2
Output High Voltage, VOH
IOH=-25mA
2.4
Output Low Voltage, VOL
IOL=25mA
IDD Operating Supply Current
No Load
18
IDD Operating Supply Current, 3.3V
No Load
10
Short Circuit Current
24.576 MHz outputs
±70
AC CHARACTERISTICS (VDD = 5.0V unless otherwise noted)
Input Frequency, crystal input
14.31818
Input Frequency, clock input
14.31818
Output Frequency
VDD = 3.0 to 5.5V
24.576
Output Clock Rise Time
0.8 to 2.0V
1
Output Clock Fall Time
2.0 to 0.8V
1
Output Clock Duty Cycle
at VDD/2
45
49 to 51
Synthesis error
Absolute Clock Period Jitter
Deviation from mean
±120
One Sigma Clock Period Jitter
50
MK1449C
Sound Clock
Maximum
7
VDD+0.5
VDD+0.5
70
260
150
5.5
(VDD/2)-1
0.4
Units
V
V
V
°C
°C
°C
V
V
V
V
V
mA
mA
mA
MHz
MHz
MHz
ns
ns
%
ppm
ps
ps
55
1
3
Revision 060198
Printed 11/15/00
MicroClock Division of ICS•1271 Parkmoor Ave.•San Jose•CA•95126•(408)295-9800tel•(408)295-9818fax
MDS 1449C A
PRELIMINARY INFORMATION
I C R O
C
LOC K
External Components / Crystal Selection
MK1449C
Sound Clock
The MK1449C requires a 0.01µF decoupling capacitor to be connected between VDD and GND. It must
be connected close to the MK1449C to minimize lead inductance. No external power supply filtering is
required for this device. A 33Ω series terminating resistor can be used next to the clock output pins. The
total on-chip crystal capacitance is approximately 13 pF, so a parallel resonant, fundamental mode crystal
should be used. For crystals with a specified load capacitance greater than 13 pF, crystal capacitors should
be connected from each of the pins X1 and X2 to ground. The value (in pF) of these crystal caps should
be = (C
L
-13)*2, where C
L
is the crystal load capacitance in pF. These external capacitors are only required
for applications where the exact frequency is critical. For a clock input, connect to X1 and leave X2
unconnected (no capacitors on either).
Package Outline and Package Dimensions
8 pin SOIC
E
Pin 1
H
Symbol
A
b
D
E
H
e
h
Q
Inches
Min
Max
0.055 0.068
0.013 0.019
0.185 0.200
0.150 0.160
0.225 0.245
.050 BSC
0.015
0.004
0.01
Millimeters
Min
Max
1.397 1.7272
0.330
0.483
4.699
5.080
3.810
4.064
5.715
6.223
1.27 BSC
0.381
0.102
0.254
D
Q
e
b
c
h x 45°
A
Ordering Information
Part/Order Number
MK1449S
MK1449STR
Marking
MK1449S
MK1449S
Package
8 pin SOIC
8 pin SOIC on tape and reel
Temperature
0-70°C
0-70°C
While the information presented herein has been checked for both accuracy and reliability, ICS/MicroClock 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/MicroClock. ICS/MicroClock reserves the right to change any circuitry or specifications without notice. ICS/MicroClock
does not authorize or warrant any ICS/MicroClock product for use in life support devices or critical medical instruments.
4
Revision 060198
Printed 11/15/00
MicroClock Division of ICS•1271 Parkmoor Ave.•San Jose•CA•95126•(408)295-9800tel•(408)295-9818fax
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