ZL30409/DDA ZARLINK [Zarlink Semiconductor Inc], ZL30409/DDA Datasheet - Page 15

• Manufacturer Part Number: ZL30409/DDA
• Description: T1/E1 System Synchronizer with Stratum 3 Holdover
• Manufacturer: ZARLINK [Zarlink Semiconductor Inc]

Applications
This section contains ZL30409 application specific details for clock and crystal operation, reset operation, power
supply decoupling, and control operation.
Master Clock
The ZL30409 can use either a clock or crystal as the master timing source.
In Freerun Mode, the frequency tolerance at the clock outputs is identical to the frequency tolerance of the source
at the OSCi pin. For applications not requiring an accurate Freerun Mode, tolerance of the master timing source
may be
the master timing source must be no greater than
Another consideration in determining the accuracy of the master timing source is the desired capture range. The
sum of the accuracy of the master timing source and the capture range of the ZL30409 will always equal 230ppm.
For example, if the master timing source is 100ppm, then the capture range will be 130ppm.
Clock Oscillator - when selecting a Clock Oscillator, numerous parameters must be considered. This includes
absolute frequency, frequency change over temperature, output rise and fall times, output levels and duty cycle.
For applications requiring
FOX F7C-2E3-20.0MHz
Frequency:
Tolerance:
Rise & Fall Time:
Duty Cycle:
The output clock should be connected directly (not AC coupled) to the OSCi input of the ZL30409, and the OSCo
output should be left open as shown in Figure 8.
Crystal Oscillator - Alternatively, a Crystal Oscillator may be used. A complete oscillator circuit made up of a
crystal, resistor and capacitors is shown in Figure 9.
±
100ppm. For applications requiring an accurate Freerun Mode, such as AT&T TR62411, the tolerance of
20MHz
25ppm 0C to 70C
10ns (0.33V 2.97V 15pF)
40% to 60%
±
32ppm clock accuracy, the following clock oscillator module may be used.
Figure 8 - Clock Oscillator Circuit
ZL30409
OSCo
OSCi
No Connection
Zarlink Semiconductor Inc.
±
ZL30409
32ppm.
20MHz OUT
+3.3V
+3.3V
15
GND
0.1uF
Data Sheet