zl50018gag2 Zarlink Semiconductor, zl50018gag2 Datasheet - Page 72

• Manufacturer Part Number: zl50018gag2
• Description: 2 K Digital Switch With Enhanced Stratum 3 Dpll
• Manufacturer: Zarlink Semiconductor

Note: LDT should be calculated as per the maximum expected amplitude of jitter on the active input reference
using the following formula:
Example: If maximum expected jitter amplitude on 2.048 MHz reference is 10UI (i.e., 10 x 488. ns = 4882 ns)
(assuming the jitter frequency where DPLL attenuation is big), the LDT should be programmed to be (4882/15.2)
x 2 = 642 = 0282
Reset Value: 000F
Reset Value: 2C00
External Read/Write Address: 0047
External Read/Write Address: 0048
15 - 0
15 - 0
Bit
Bit
LDT
LDI
15
15
15
15
LDT
LDI
14
14
14
14
LDT15 - 0
LDI15 - 0
Name
Name
H
H
LDT
LDI
13
13
13
13
H
LDT
Lock Detect Threshold Bits
The binary value of these bits defines the upper limit of the absolute phase from the
phase detector output for lock detection.
When the value of the absolute phase is less than or equal to LDT for duration of time
defined by the LDIR register, the DPLL locks.
When the value of the absolute phase is greater than LDT for duration of time defined by
the LDIR register divided by 256, the DPLL does not lock.
Lock Detector Interval Bits
The binary value of these bits defines the time interval that the output phase detector
must be below the lock detect threshold to declare lock. Unsigned representation of the
LDI bits is defined in 4 ms intervals.
LDI
12
12
12
12
Table 36 - Lock Detector Threshold Register (LDTR) Bits
Table 37 - Lock Detector Interval Register (LDIR) Bits
H
H
LDT
LDI
11
11
11
11
LDT
LDI
10
10
10
10
LDT = MAX_EXP_JITTER (ns) x 2
LDT
LDI
9
9
9
9
Zarlink Semiconductor Inc.
ZL50018
LDT
LDI
15.2 (ns)
8
8
8
8
72
LDT
LDI
7
7
7
7
Description
Description
LDT
LDI
6
6
6
6
LDT
LDI
5
5
5
5
LDT
LDI
4
4
4
4
LDT
LDI
3
3
3
3
LDT
LDI
2
2
2
2
Data Sheet
LDT
LDI
1
1
1
1
LDT
LDI
0
0
0
0