7.3 Fault Monitoring
The Si5391 provides fault indicators which monitor loss of signal (LOS) of the inputs (IN0, IN1, IN2, XA/XB, FB_IN) and loss of lock
(LOL) for the PLL, as shown in the diagram below. These fault conditions, as well as other internal status indications, are provided
through a combination of internal registers and externally provided signals (LOLb and INTRb). Usage and configuration of status/fault
monitoring features, as well as mapping these to the INTRb output, are described on following sub sections.
PLL
LPF
PD
Mn
IN0
IN0b
LOS0
÷P
0
IN1
IN1b
÷P
1
FB_IN
FB _INb
IN2
IN2b
÷P
2
LOL
Si5391
XB
XA
OSC
÷P
fb
Md
÷
LOSXAB
LOS1
LOS2
LO
Lb
IN
T
Rb
LOSFB
Figure 7.5. Fault Monitors
Si5391 Reference Manual • Clock Inputs
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
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Rev. 0.5 • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice • January 11, 2022
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