ZL30106_05 ZARLINK [Zarlink Semiconductor Inc], ZL30106_05 Datasheet - Page 31

• Manufacturer Part Number: ZL30106_05
• Description: SONET/SDH/PDH Network Interface DPLL
• Manufacturer: ZARLINK [Zarlink Semiconductor Inc]

6.0
This section contains ZL30106 application specific details for power supply decoupling, reset operation, clock and
crystal operation.
6.1
Jitter levels on the ZL30106 output clocks may increase if the device is exposed to excessive noise on its power
pins. For optimal jitter performance, the ZL30106 device should be isolated from noise on power planes connected
to its 3.3 V and 1.8 V supply pins. For recommended common layout practices, refer to Zarlink Application Note
ZLAN-178.
6.2
The ZL30106 can use either a clock or crystal as the master timing source. Zarlink application note ZLAN-68 lists a
number of applicable oscillators and crystals that can be used with the ZL30106.
6.2.1
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, duty cycle and phase noise.
The output clock should be connected directly (not AC coupled) to the OSCi input of the ZL30106, and the OSCo
output should be left open as shown in Figure 19.
6.2.2
Alternatively, a Crystal Oscillator may be used. A complete oscillator circuit made up of a crystal, resistor and
capacitors is shown in Figure 20.
The accuracy of a crystal oscillator depends on the crystal tolerance as well as the load capacitance tolerance.
Typically, for a 20 MHz crystal specified with a 32 pF load capacitance, each 1 pF change in load capacitance
Power Supply Decoupling
Master Clock
Applications
Clock Oscillator
Crystal Oscillator
1
2
3
4
Table 7 - Typical Clock Oscillator Specification
Frequency
Tolerance
Rise & fall time
Duty cycle
ZL30106
Figure 19 - Clock Oscillator Circuit
OSCo
Zarlink Semiconductor Inc.
OSCi
No Connection
ZL30106
31
20 MHz OUT
20 MHz
as required
< 10 ns
40% to 60%
+3.3 V
+3.3 V
GND
0.1 µF
Data Sheet