ICST MK2011 Fast ethernet clock source Datasheet

MK2011
Fast Ethernet Clock Source
I C R O C LOC K
Description
Features
The MK2011 is the ideal way to generate clocks
for Fast Ethernet cards or systems. It provides
20MHz, 25MHz, and 50MHz clocks. In an 8 pin
SOIC, the MK2011 can save component count,
board space, and cost over surface mount crystals
and oscillators, and increase reliability by
eliminating two or three mechanical devices from
the board.
• Packaged in 8 pin SOIC
MicroClock offers many other clocks for
computers and computer peripherals. Consult
MicroClock when you need to remove crystals and
oscillators from your board.
• Input crystal or clock frequency of 20.00 MHz
• Lowest jitter in the industry reliably clocks
sensitive Ethernet devices.
• Output clock frequencies of 20.00 MHz,
25.00 MHz, and 50.00 MHz
• 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
PLL
Clock Synthesis
Circuitry
20.00 MHz
xtal or clock
Output
Buffer
50 MHz
Output
Buffer
25 MHz
Output
Buffer
20 MHz
X1
Crystal
Oscillator
X2
1
Revision 120597
Printed 11/15/00
MicroClock Division of ICS•1271 Parkmoor Ave.•San Jose•CA•95126•(408)295-9800tel•(408)295-9818fax
MDS 2011 B
MK2011
Fast Ethernet Clock Source
I C R O C LOC K
Suggested Layout
Pin Assignment
20.00 MHz in
(crystal caps not
shown)
Pin 1
X1/ICLK
1
8
X2
VDD
2
7
20M
GND
3
6
GND
25M
4
5
50M
V
2
7
3
6
4
5
G
33Ω (optional)
25MHz out
Pin Descriptions
Number
1
2
3
4
5
6
7
8
Name
X1/ICLK
VDD
GND
25M
50M
GND
20M
X2
Type
I
P
P
O
O
P
O
O
20MHz
out
33Ω (optional)
0.1µF
8 pin SOIC
8
33Ω (optional)
50MHz out
Description
Crystal Connection. Connect to a 20.000 MHz crystal or clock.
Connect to +5V.
Connect to ground.
25.000 MHz clock output.
50.000 MHz clock output.
Connect to ground.
20.000 MHz buffered crystal clock output.
Crystal Connection to a 20.000 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. For a crystal input, one
22pF load capacitor should be connected to each of the X1 and X2 pins and ground, and a parallel
resonant 20.000 MHz, 16pF load, crystal is recommended. The frequency tolerance of the crystal should
be 50ppm or better. For a clock input, connect to X1 and leave X2 unconnected. A decoupling capacitor of
0.1µF should be connected between VDD and GND on pins 2 and 3, and 33Ω terminating resistors
should be used on clock outputs with traces longer than 1 inch.
2
Revision 120597
Printed 11/15/00
MicroClock Division of ICS•1271 Parkmoor Ave.•San Jose•CA•95126•(408)295-9800tel•(408)295-9818fax
MDS 2011 B
I C R O C LOC K
MK2011
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
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
20.0000
MHz
Input Crystal Accuracy
50
ppm
Input Clock Duty Cycle, 20.000MHz
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, 20 MHz output
-400
250
400
ps
Absolute Clock Period Jitter, 50, 25 MHz clocks
-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
Revision 120597
Printed 11/15/00
MicroClock Division of ICS•1271 Parkmoor Ave.•San Jose•CA•95126•(408)295-9800tel•(408)295-9818fax
MDS 2011 B
MK2011
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 1.7272
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
A
c
e
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
b
Ordering Information
Part/Order Number
MK2011S
MK2011STR
Marking
MK2011S
MK2011S
Package
8 pin SOIC
Add tape and reel
Temperature
0-70°C
0-70°C
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.
4
Revision 120597
Printed 11/15/00
MicroClock Division of ICS•1271 Parkmoor Ave.•San Jose•CA•95126•(408)295-9800tel•(408)295-9818fax
MDS 2011 B
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