zl30109 Zarlink Semiconductor, zl30109 Datasheet - Page 18

• Manufacturer Part Number: zl30109
• Description: Ds1/e1 System Synchronizer With 19.44 Mhz Output
• Manufacturer: Zarlink Semiconductor

4.2
The loop filter settings can be selected through the BW_SEL pin, see Table 2.
4.3
The output clock and frame pulses of the frequency synthesizers are available in two groups controlled by the
OUT_SEL input. Table 3 lists the supported combinations of output clocks and frame pulses.
4.4
The ZL30109 has three possible manual modes of operation; Normal, Holdover and Freerun. These modes are
selected with the mode select pins MODE_SEL1 and MODE_SEL0 as is shown in Table 4. Transitioning from one
mode to the other is controlled by an external controller.
4.4.1
Freerun mode is typically used when an independent clock source is required, or immediately following system
power-up before network synchronization is achieved.
In Freerun mode, the ZL30109 provides timing and synchronization signals which are based on the master clock
frequency (supplied to OSCi pin) only, and are not synchronized to the reference input signals.
The Freerun accuracy of the output clock is equal to the accuracy of the master clock (OSCi). So if a
output clock is required, the master clock must also be
BW_SEL
Loop Filter Selection
Output Clock and Frame Pulse Selection
Modes of Operation
Freerun Mode
0
1
1
1
OUT_SEL
MODE_SEL1
0
1
0
0
1
1
Detected REF Frequency
8.192 MHz, 16.384 MHz,
1.544 MHz, 2.048 MHz,
C1.5o, C2o, C16o, C32o, C65o, C19o
C1.5o, C2o, C4o, C8o, C16o, C19o
Table 3 - Clock and Frame Pulse Selection
MODE_SEL0
19.44 MHz
2 kHz
8 kHz
any
Generated Clocks
0
1
0
1
Table 2 - Loop Filter Settings
Table 4 - Operating Modes
Zarlink Semiconductor Inc.
ZL30109
±
18
32 ppm. See Applications - Section 6.2, “Master Clock“.
Normal (with automatic Holdover)
reserved (must not be used)
Loop Filter Bandwidth
Holdover
Freerun
922 Hz
1.8 Hz
14 Hz
58 Hz
Mode
Generated Frame Pulses
F16o, F32o, F65o, F2ko
F4o, F8o, F16o, F2ko
Phase Slope Limiting
9.5 ms/s
9.5 ms/s
9.5 ms/s
61 µ/s
Data Sheet
±
32 ppm