zl30112 Zarlink Semiconductor, zl30112 Datasheet - Page 8

• Manufacturer Part Number: zl30112
• Description: Slic/codec Dpll
• Manufacturer: Zarlink Semiconductor

4.0
Normal Mode
In Normal mode, the ZL30112 provides timing and frame synchronization signals which are synchronized to the
reference input (REF). The input reference signal may have a nominal frequency of 8 kHz, 2.048 MHz, 8.192 MHz,
or 19.44 MHz. The frequency of the reference inputs are automatically detected by the reference monitors.
Automatic Freerun Mode
Automatic freerun mode is typically used for short durations while system synchronization is temporarily disrupted.
In Automatic freerun mode, the ZL30112 provides timing and synchronization signals, which are not locked to an
external reference signal, but are based on the freerun accuracy of the external oscillator.
5.0
The following are some PLL performance indicators and their corresponding definitions.
5.1
Timing jitter is defined as the high frequency variation of the clock edges from their ideal positions in time. Wander
is defined as the low-frequency variation of the clock edges from their ideal positions in time. High and low
frequency variation imply phase oscillation frequencies relative to some demarcation frequency. (Often 10 Hz or
20 Hz for DS1 or E1, higher for SONET/SDH clocks.) Jitter parameters given in this data sheet are total timing jitter
numbers, not cycle-to-cycle jitter.
5.2
Jitter tolerance is a measure of the ability of a PLL to operate properly (i.e., remain in lock and or regain lock in the
presence of large jitter magnitudes at various jitter frequencies) when jitter is applied to its reference. The applied
jitter magnitude and jitter frequency depends on the applicable standards.
REF_DIS=1: Current selected reference disrupted (see Figure 3)
Jitter Generation (Intrinsic Jitter)
Jitter Tolerance
Modes of Operation
Measures of Performance
RST
freerun
REF_DIS=1
Figure 5 - Modes of Operation
Zarlink Semiconductor Inc.
ZL30112
REF_DIS=0
REF_DIS=1
8
(locked)
Normal
REF_DIS=0
TIE Correction
Data Sheet