AD9518-4
Data Sheet
Rev. B | Page 52 of 64
Reg.
Addr.
(Hex)
Bits
Name
Description
0x01B
7
Enables or disables VCO frequency monitor.
VCO frequency
monitor
0: disables VCO frequency monitor (default).
1: enables VCO frequency monitor.
6
Enables or disables REF2 frequency monitor.
REF2 (REFIN)
frequency monitor
0: disables REF2 frequency monitor (default).
1: enables REF2 frequency monitor.
5
REF1 (REFIN)
frequency monitor
REF1 (REFIN) frequency monitor enable; this is for both REF1 (single-ended) and REFIN (differential) inputs
(as selected by differential reference mode).
0: disables REF1 (REFIN) frequency monitor (default).
1: enables REF1 (REFIN) frequency monitor.
[4:0]
Selects the signal that is connected to the REFMON pin.
REFMON pin
control
4
3
2
1
0
Level or
Dynamic
Signal
Signal at REFMON Pin
0
LVL
Ground (dc) (default).
0
1
DYN
REF1 clock (differential reference when in differential mode).
0
1
0
DYN
REF2 clock (not available in differential mode).
0
1
DYN
Selected reference to PLL (differential reference when in differential mode).
0
1
0
DYN
Unselected reference to PLL (not available in differential mode).
0
1
0
1
LVL
Status of selected reference (status of differential reference); active high.
0
1
0
LVL
Status of unselected reference (not available in differential mode); active
high.
0
1
LVL
Status REF1 frequency; active high.
0
1
0
LVL
Status REF2 frequency; active high.
0
1
0
1
LVL
(Status REF1 frequency) AND (status REF2 frequency).
0
1
0
1
0
LVL
(DLD) AND (status of selected reference) AND (status of VCO).
0
1
0
1
LVL
Status of VCO frequency; active high.
0
1
0
LVL
Selected reference (low = REF1, high = REF2).
0
1
0
1
LVL
Digital lock detect (DLD); active low.
0
1
0
LVL
Holdover active; active high.
0
1
LVL
LD pin comparator output; active high.
1
0
LVL
VS (PLL supply).
1
0
1
DYN
REF1 clock (differential reference when in differential mode).
1
0
1
0
DYN
REF2 clock (not available in differential mode).
1
0
1
DYN
Selected reference to PLL (differential reference when in differential mode).
1
0
1
0
DYN
Unselected reference to PLL (not available in differential mode).
1
0
1
0
1
LVL
Status of selected reference (status of differential reference); active low.
1
0
1
0
LVL
Status of unselected reference (not available in differential mode); active low.
1
0
1
LVL
Status of REF1 frequency; active low.
1
0
LVL
Status of REF2 frequency; active low.
1
0
1
LVL
(Status of REF1 frequency) AND (Status of REF2 frequency).
1
0
1
0
LVL
(DLD) AND (Status of selected reference) AND (Status of VCO).
1
0
1
LVL
Status of VCO frequency; active low.
1
0
LVL
Selected reference (low = REF2, high = REF1).
1
0
1
LVL
Digital lock detect (DLD); active low.
1
0
LVL
Holdover active; active low.
1
LVL
LD pin comparator output; active low.