ICST MK2014ATR Fast ethernet clock source Datasheet

MK2014A
Fast Ethernet Clock Source
I C R O C LOC K
Description
Features
The MK2014A is the ideal way to generate clocks
for Fast Ethernet cards or systems. It provides
20MHz and 25MHz clocks from an inexpensive
14.31818 MHz crystal or clock. In an 8 pin SOIC,
the MK2014A can save component count, board
space, and cost over surface mount crystals and
oscillators, and increase reliability by eliminating
mechanical devices from the board.
• Packaged in 8 pin SOIC
The MK2014A is a functionally identical update
of the MK2014 and should be used in all designs.
The only change is in crystal load capacitance as
stated on page 2.
MicroClock offers many other clocks for
computers and computer peripherals. Consult your
MicroClock representative when you need to
remove crystals and oscillators from your board.
• Input crystal or clock frequency of 14.318 MHz
• Lowest jitter in the industry reliably clocks
sensitive Ethernet devices.
• Output clock frequencies of 20.00 MHz and
25.00 MHz
• Zero ppm synthesis error in the output clocks
• Full CMOS outputs with 25mA drive capability
at TTL levels
• 3.3V or 5V±10% supply voltage
• Advanced, low power CMOS process
• Insensitive to input clock duty cycle
Block Diagram
VDD GND
2
Clock Synthesis
and Control
Circuitry
14.31818 MHz
crystal or clock
Output
Buffer
20 MHz
Output
Buffer
25 MHz
Output
Buffer
14.318 MHz
X1
Crystal
Oscillator
X2
1
Revision 121598
Printed 11/15/00
MicroClock Division of ICS • 525 Race Street • San Jose • CA • 95126•(408)295-9800tel•(408)295-9818fax
MDS 2014A B
MK2014A
Fast Ethernet Clock Source
I C R O C LOC K
Suggested Layout
Pin Assignment
14.3 MHz in
(crystal caps not
shown)
Pin 1
X1/ICLK
1
8
X2
VDD
2
7
14M
GND
3
6
20M
25M
4
5
GND
V
0.1µF
8 pin SOIC
G
8
14.3MHz
out
2
7
3
6
33Ω (optional) 20MHz
out
5
33Ω (optional)
4
33Ω (optional)
25MHz out
Pin Descriptions
Number
1
2
3
4
5
6
7
8
Name
X1/ICLK
VDD
GND
25M
GND
20M
14M
X2
Type
XI
P
P
O
P
O
O
XO
Description
Crystal Connection. Connect to a 14.31818 MHz crystal or clock.
Connect to +5V.
Connect to ground.
25.000 MHz clock output.
Connect to ground.
20.000 MHz clock output.
14.31818 MHz buffered crystal clock output.
Crystal Connection to a 14.31818 MHz crystal, or leave unconnected for clock input.
Key: I = Input, O = output, P = power supply connection
External Components/Crystal Selection
A minimum number of external components are required for proper oscillation. A decoupling capacitor of
0.1 µF should be connected between VDD and GND on pins 2 and 3, and 33 Ω terminating resistors
should be used on clock outputs with traces longer than 1 inch. For a clock input, connect to X1 and leave
X2 unconnected. For a crystal input, a parallel resonant 14.31818 MHz crystal is recommended. The
frequency accuracy of the crystal should be 30 ppm or better. External capacitors from each of the X1 and
X2 pins to ground should be added with a value in pF equal to (CL -13)*2, where CL is the crystal load
capacitance in pF. So for a crystal with load capacitance of 16 pF, 6 pF capacitors should be used. [Note
that the MK2014S required crystal load capacitors of (CL -4)*2.]
2
Revision 121598
Printed 11/15/00
MicroClock Division of ICS • 525 Race Street • San Jose • CA • 95126•(408)295-9800tel•(408)295-9818fax
MDS 2014A B
I C R O C LOC K
MK2014A
Fast Ethernet Clock Source
Electrical Specifications
Parameter
Conditions
Minimum
Typical
Maximum
Units
7
VDD+.5V
VDD+.5V
70
260
150
V
V
V
°C
°C
°C
5.5
V
V
V
V
V
V
mA
mA
pF
ppm
ABSOLUTE MAXIMUM RATINGS (note 1)
Supply Voltage, VDD
Inputs
Clock Outputs
Ambient Operating Temperature
Soldering Temperature
Storage temperature
Referenced to GND
Referenced to GND
Referenced to GND
-0.5
-0.5
0
Max of 20 seconds
-65
DC CHARACTERISTICS (at 5.0V unless otherwise noted)
Operating Voltage, VDD
Input High Voltage, VIH, input clock only
Input Low Voltage, VIL, input clock only
Output High Voltage, VOH
Output High Voltage, VOH
Output Low Voltage, VOL
Operating Supply Current, IDD, 5V
Operating Supply Current, IDD, 3.3V
Input Capacitance
Actual Mean Frequency versus Target, note 3
Clock input
Clock input
IOH=-4mA
IOH=-25mA
IOL=25mA
No Load
No Load
With exact crystal
4.5
3.5
2.5
2.5
1.5
VDD-0.4
2.4
0.4
19
10
7
0
AC CHARACTERISTICS
Input Clock or Crystal Frequency
14.31818
MHz
Input Crystal Accuracy
30
ppm
Input Clock Duty Cycle, 14.31818MHz
Time above 2.5V
20
80
%
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
Time above 1.5V
45
50
55
%
Absolute Clock Period Jitter, 14.318 MHz output
-400
250
400
ps
Absolute Clock Period Jitter, 20, 25 MHz outputs
-300
150
300
ps
One Sigma Clock Period Jitter
All outputs
70
ps
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. Typical values are at 25°C.
3. Provided an exact clock input or a properly tuned crystal is used as the reference.
3
Revision 121598
Printed 11/15/00
MicroClock Division of ICS • 525 Race Street • San Jose • CA • 95126•(408)295-9800tel•(408)295-9818fax
MDS 2014A B
MK2014A
Fast Ethernet Clock Source
I C R O C LOC K
Package Outline and Package Dimensions
8 pin SOIC
E
Symbol
A
b
D
E
H
e
h
Q
H
Pin 1
h x 45°
D
Q
Millimeters
Min
Max
1.397
1.778
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
A
c
e
Inches
Min
Max
0.055 0.070
0.013 0.019
0.185 0.200
0.150 0.160
0.225 0.245
.050 BSC
0.015
0.004
0.01
b
Ordering Information
Part/Order Number
MK2014A
MK2014ATR
Marking
MK2014A
MK2014A
Package
8 pin SOIC
Add tape and reel
Temperature
0 to 70 C
0 to 70 C
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.
4
Revision 121598
Printed 11/15/00
MicroClock Division of ICS • 525 Race Street • San Jose • CA • 95126•(408)295-9800tel•(408)295-9818fax
MDS 2014A B
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