DS3105 Maxim Integrated Products, DS3105 Datasheet - Page 30

• Manufacturer Part Number: DS3105
• Description: Line Card Timing IC
• Manufacturer: Maxim Integrated Products

Table 7-5. T0 DPLL adaptation for the T4 DPLL Phase Measurement Mode
Notes:
1.
2.
3.
7.7.11 Input Jitter Tolerance
The device is compliant with the jitter tolerance requirements of the standards listed in
±360° / ±180° PFD, jitter can be tolerated up to the point of eye closure. Either LOCK8K mode (see section 7.4.2.2)
or the multi-cycle phase detector (see section 7.7.5) should be used for high jitter tolerance.
7.7.12 Jitter Transfer
The transfer of jitter from the selected reference to the output clocks has a programmable transfer function that is
determined by the DPLL bandwidth. (See section 7.7.3.) In the T0 DPLL, the 3-dB corner frequency of the jitter
transfer function can be set to any of 13 positions from 0.1 Hz to 400 Hz. In the T4 DPLL the 3-dB corner frequency
of the jitter transfer function can be set to various values from 18 Hz to 70 Hz.
7.7.13 Output Jitter and Wander
Several factors contribute to jitter and wander on the output clocks, including:
The DPLL in the device has programmable bandwidth (see section 7.7.3). With respect to jitter, the DPLL behaves
as a low-pass filter with a programmable pole. The bandwidth of the DPLL is low enough to strongly attenuate most
jitter.
Locking Mode
for T4 Forced
Reference
LOCK8K or
DIVN(8K)
LOCK8K or
DIVN(8K)
LOCK8K or
DIVN(8K)
LOCK8K or
DIVN(8K)
DIVN (not 8K)
DIRECT
In this case the T0 select reference must be the same frequency as the T4 selected reference.
If the T4 selected reference frequency is 8 kHz and the T0 selected reference is a different frequency, the two references can be compared
by configuring the T4 forced reference for 8 kHz and LOCK8K mode. This forces the copy of the T0 selected reference to be divided down
to 8 kHz using either LOCK8K or DIVN mode.
DIVN(8K) means that the FREQ field is set to 8 kHz, DIVN(not 8K) means the FREQ field is not set to 8 kHz.
Confidential. Document Issued Under Non-Disclosure Agreement. Confidential. Document Issued Under Non-Disclosure Agreement.
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Jitter and wander amplitude on the selected reference (while in the locked state)
The jitter transfer characteristic of the device (while in the locked state)
The jitter and wander on the local oscillator clock signal (especially wander while in the
holdover state)
Locking Mode
for T0 Selected
Reference
DIRECT
LOCK8K
DIVN (8K)
DIVN (not 8K)
any
any
Preliminary. Subject to Change Without Notice.
Locking Mode
for Copy of T0
Selected Ref
LOCK8K
LOCK8K
DIVN
DIRECT
DIRECT
DIRECT
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Frequency of the T4
Forced Ref for T4MT0
Phase Measurement
8 kHz
8 kHz
8 kHz
8 kHz
same as the T4 forced
ref input frequency
same as the T4 forced
ref input frequency
Frequency of the T0
Selected Ref for T4MT0
Phase Measurement
8 kHz
8 kHz
8 kHz
8 kHz
same as the T0 selected
ref input frequency
same as the T0 selected
ref input frequency
Table
1-1. When using the
(1)
(1)
DS3105