mk2049-01 ETC-unknow, mk2049-01 Datasheet - Page 6

• Manufacturer Part Number: mk2049-01
• Description: Communications Clock
• Manufacturer: ETC-unknow

MDS 2049-01 J
Integrated Circuit Systems, Inc. • 525 Race Street • San Jose • CA • 95126 • [phone]tel •www.icst.com
LAYOUT AND EXTERNAL COMPONENTS (continued)
Loop Filter Components
The external loop filter should be connected between CAP1 and CAP2 as shown in Figure 2 below, and as
close to the chip as possible. Be sure to follow the recommendations on capacitor types described on page 6.
Crystal Operation
The MK2049 operates by phase locking the input signal to a VCXO which consists of the special
recommended crystal and the integrated VCXO oscillator circuit on the MK2049. To achieve the best
performance and reliability, the layout guidelines shown on the previous page must be closely followed.
The frequency of oscillation of a quartz crystal is determined by its cut and by the load capacitors connected
to it. The MK2049 has variable load capacitors on-chip which “pull”, or change the frequency of the crystal.
External stray capacitance must be kept to a minimum to ensure maximum pullability of the crystal. To
achieve this, the layout should use short traces between the MK2049 and the crystal.
department at [phone] for the recommended values for your application.
Typical component values are shown. Contact the ICS MicroClock applications
Figure 2. Loop Filter component values for most configurations
CAP2
CAP1
1.5 nF
6
7.5 M
0.030 µF
Communications Clock PLL
MK2049-01
Revision 040601