DataSheet8.cn


PDF ( 数据手册 , 数据表 ) MK2049-01

零件编号 MK2049-01
描述 Communications Clock PLL
制造商 Integrated Circuit Systems
LOGO Integrated Circuit Systems LOGO 


1 Page

No Preview Available !

MK2049-01 数据手册, 描述, 功能
MK2049-01
Communications Clock PLL
Description
The MK2049 is a Phase-Locked Loop (PLL) based
clock synthesizer, which accepts an 8 kHz clock
input as a reference and generates T1, E1, T3, E3,
and OC3 frequencies. The device can also accept a
T1, E1, T3, or E3 input clock and provide the
same output for loop timing. All outputs are
frequency locked together and to the input. This
allows for the generation of locked clocks to an
8 kHz backplane clock, simplifying clock
distribution in communications systems.
MicroClock can customize this device for many
other different frequencies. Contact your
MicroClock representative for more details.
For a fixed input-output phase relationship, refer
to the MK2049-02, -03, or -3x. The MK2049-3x
are 3.3 V devices.
Block Diagram
VDD GND
44
Features
• Packaged in 20 pin SOIC
• Meets the TR62411, ETS300 011, and GR-1244
specification for MTIE, Pull-in/Hold-in Range,
Phase Transients, and Jitter Generation for
Stratum 3, 4, and 4E
• Accepts multiple inputs: 8 kHz backplane clock or
Loop Timing frequencies
• Locks to 8 kHz ±100 ppm (External mode)
• Exact internal ratios eliminate the need for external
dividers
• Zero ppm synthesis error in all output clocks.
• Output clock rates include T1, E1, T3, E3, and
OC3÷8
• 5 V ±5% operation
• Offered in Commercial and Industrial temperature
versions
FS3:0 4
Clock
Input
Reference
Crystal
X1
Crystal
Oscillator
X2
External/
Loop
Timing
Mux
PLL
Clock
Synthesis,
Control, and
Jitter
Attenuation
Circuitry
Output
Buffer
Output
Buffer
Output
Buffer
CLK1
CLK2
8 kHz
CAP1
CAP2
MDS 2049-01 J
1
Revision 040601
Integrated Circuit Systems, Inc. • 525 Race Street • San Jose • CA • 95126 • (408)295-9800tel •www.icst.com







MK2049-01 pdf, 数据表
MK2049-01
Communications Clock PLL
LAYOUT AND EXTERNAL COMPONENTS (continued)
Determining the Crystal Frequency Adjustment Capacitors
To determine the crystal adjustment capacitor values, you will need a PC board of your final layout, a
frequency counter capable of less than 1 ppm resolution and accuracy, two power supplies, and some samples
of the crystals which you plan to use in production, along with measured initial accuracy for each crystal at
the specified load capacitance, CL .
To determine the value of the crystal capacitors:
1. Connect VDD of the MK2049 to 5.0 V. Connect pin 18 of the MK2049 to the second power supply.
Adjust the voltage on pin 18 to 0.0 V. Measure and record the frequency of the CLK1 or CLK2 output .
2. Adjust the voltage on pin 18 to 3.0 V. Measure and record the frequency of the same output.
To calculate the centering error:
Centering
error
= 106
(f3.0V - ftarget) + (f0.0V - ftarget)
ftarget
- errorxtal
Where ftarget = 44.736000 MHz, for example, and errorxtal = actual initial accuracy (in ppm) of the
crystal being measured.
If the centering error is less than ±15 ppm, no adjustment is needed. If the centering error is more than
15 ppm negative, the PC board has too much stray capacitance and will need to be redone with a new layout
to reduce stray capacitance. (The crystal may be re-specified to a lower load capacitance instead. Contact ICS
MicroClock for details.) If the centering error is more than 15 ppm positive, add identical fixed centering
capacitors from each crystal pin to ground. The value for each of these caps (in pF) is given by:
External Capacitor = 2*(centering error)/(trim sensitivity)
Trim sensitivity is a parameter which can be supplied by your crystal vendor. If you do not know the value,
assume it is 30 ppm/pF. After any changes, repeat the measurement to verify that the remaining error is
acceptably low (less than ±15 ppm).
The MicroClock Applications department can perform this procedure on your board. Call us at 408-295-
9800, and we will arrange for you to send us a PC board (stuffed or unstuffed) and one of your crystals. We
will calculate the value of capacitors needed.
MDS 2049-01 J
8
Revision 040601
Integrated Circuit Systems, Inc. • 525 Race Street • San Jose • CA • 95126 • (408)295-9800tel •www.icst.com














页数 11 页
下载[ MK2049-01.PDF 数据手册 ]


分享链接

Link :

推荐数据表

零件编号描述制造商
MK2049-01Communications Clock PLLIntegrated Circuit Systems
Integrated Circuit Systems
MK2049-02Communications Clock PLLsIntegrated Circuit Systems
Integrated Circuit Systems
MK2049-03Communications Clock PLLsIntegrated Circuit Systems
Integrated Circuit Systems

零件编号描述制造商
STK15C88256-Kbit (32 K x 8) PowerStore nvSRAMCypress Semiconductor
Cypress Semiconductor
NJM4556DUAL HIGH CURRENT OPERATIONAL AMPLIFIERNew Japan Radio
New Japan Radio
EL1118-G5 PIN LONG CREEPAGE SOP PHOTOTRANSISTOR PHOTOCOUPLEREverlight
Everlight


DataSheet8.cn    |   2020   |  联系我们   |   搜索  |  Simemap