6.2. PLL Self-Calibration. Silicon Laboratories SI5369, SI5322, SI5327, SI5326, SI5366, SI5319, SI5316, SI5325, SI5367, SI5368
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Si53xx-RM
6.2. PLL Self-Calibration
An internal self-calibration (ICAL) is performed before operation to optimize loop parameters and jitter performance. While the self-calibration is being performed, the DSPLL is being internally controlled by the selfcalibration state machine, and the LOL alarm will be active for narrowband parts. The self-calibration time t
LOCKHW
is given in Table 8, “AC Characteristics—All Devices”.
Any of the following events will trigger a self-calibration:
Power-on-reset (POR)
Release of the external reset pin RST (transition of RST from 0 to 1)
Change in FRQSEL, FRQTBL, BWSEL, or RATE pins
Internal DSPLL registers out-of-range, indicating the need to relock the DSPLL.
In any of the above cases, an internal self-calibration will be initiated if a valid input clock exists (no input alarm) and is selected as the active clock at that time. For the Si5316, Si5323 and Si5366, the external crystal or reference clock must also be present for the self-calibration to begin. If valid clocks are not present, the selfcalibration state machine will wait until they appear, at which time the calibration will start. All outputs are on during the calibration process.
After a successful self-calibration has been performed with a valid input clock, no subsequent self-calibrations are performed unless one of the above conditions are met. If the input clock is lost following self-calibration, the device enters digital hold mode. When the input clock returns, the device relocks to the input clock without performing a self-calibration. (Narrow band devices only).
6.2.1. Input Clock Stability during Internal Self-Calibration (Si5316, Si5322, Si5323, Si5365, Si5366)
An exit from reset must occur when the selected CKINn clock is stable in frequency with a frequency value that is within the operating range that is reported by DSPLLsim. The other CKINs must also either be stable in frequency or squelched during a reset.
6.2.2. Self-Calibration caused by Changes in Input Frequency (Si5316, Si5322, Si5323, Si5365, Si5366)
If the selected CKINn varies by 500 ppm or more in frequency since the last calibration, the device may initiate a self-calibration.
6.2.3. Recommended Reset Guidelines (Si5316, Si5322, Si5323, Si5365, Si5366)
Rev. 0.5
65
S i 5 3 x x - R M
71
80
95
61
66
67
68
69
70
51
54
55
60
Pin #
4
32
42
19
20
22
23
2
11
14
15
24
25
26
27
30
33
Pin # Si5316 Pin
Name
N/A
RATE 0
DBL_BY
RATE1
N/A
N/A
BWSEL0
BWSEL1
FRQSEL0
FRQSEL1
N/A
N/A
SFOUT1
SFOUT0
Table 20. Si5316, Si5322, and Si5323 Pins and Reset
Must Reset after Changing Si5322 Pin
Name
FRQTBL
N/A
DBL2_BY
N/A
N/A
N/A
BWSEL0
BWSEL1
FRQSEL0
FRQSEL1
FRQSEL2
FRQSEL3
N/A
N/A
Si5323 Pin
Name
FRQTBL
RATE 0
DBL2_BY
RATE1
DEC
INC
BWSEL0
BWSEL1
FRQSEL0
FRQSEL1
FRQSEL2
FRQSEL3
SFOUT1
SFOUT0
No
No
Yes
Yes
Yes
Yes
No
Yes
Yes
Yes
Yes
Yes
No, but skew not guaranteed without Reset
No, but skew not guaranteed without Reset
Table 21. Si5365 and Si5366 Pins and Reset
Si5365 Pin Name
FRQTBL
N/A
N/A
N/A
N/A
N/A
BWSEL0
BWSEL1
DIV34_0
DIV34_1
FRQSEL0
FRQSEL1
FRQSEL2
FRQSEL3
N/A
N/A
Si5366 Pin Name
FRQTBL
RATE 0
RATE 1
CK_CONF
DEC
INC
BSWEL0
BWSEL1
DIV34_0
DIV34_1
FRQSEL0
FRQSEL1
FRQSEL2
FRQSEL3
SFOUT1
SFOUT0
Must Reset after Changing
Yes
Yes
Yes
Yes
No
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
No, but skew not guaranteed without Reset
No, but skew not guaranteed without Reset
66 Rev. 0.5
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