AD9517-3 Datasheet, PDF (65/80 Pages) Analog Devices – 12-Output Clock Generator with Integrated 2.0 GHz VCO

Data Sheet
AD9517-3
Reg.
Addr.
(Hex)
Bits Name
Description
2
REF2 power-on This bit turns the REF2 power on.
0: REF2 power off (default).
1: REF2 power on.
1
REF1 power-on This bit turns the REF1 power on.
0: REF1 power off (default).
1: REF1 power on.
0
Differential
reference
Selects the PLL reference mode, differential or single-ended. Single-ended must be selected for the automatic
switchover between REF1 and REF2 to work.
0: single-ended reference mode (default).
1: differential reference mode.
0x01D 4
PLL status
Disables the PLL status register readback.
register disable 0: PLL status register enable (default).
1: PLL status register disable.
3
LD pin comparator Enables the LD pin voltage comparator. This function is used with the LD pin current source lock detect mode. When
enable
in the internal (automatic) holdover mode, this function enables the use of the voltage on the LD pin to determine if
the PLL was previously in a locked state (see Figure 53). Otherwise, this function can be used with the REFMON and
STATUS pins to monitor the voltage on this pin.
0: disables LD pin comparator; internal/automatic holdover controller treats this pin as true (high) (default).
1: enables LD pin comparator.
2
Holdover enable Along with Bit 0, enables the holdover function. Automatic holdover must be disabled during VCO calibration.
0: holdover disabled (default).
1: holdover enabled.
1
External
Enables the external hold control through the SYNC pin. (This disables the internal holdover mode.)
holdover control 0: automatic holdover mode—holdover controlled by automatic holdover circuit. (default)
1: external holdover mode—holdover controlled by SYNC pin.
0
Holdover enable Along with Bit 2, enables the holdover function. Automatic holdover must be disabled during VCO calibration.
0: holdover disabled (default).
1: holdover enabled.
0x01F 6
VCO cal finished Read-only register: indicates status of the VCO calibration.
0: VCO calibration not finished.
1: VCO calibration finished.
5
Holdover active Read-only register: indicates if the part is in the holdover state (see Figure 53). This is not the same as holdover enabled.
0: not in holdover.
1: holdover state active.
4
REF2 selected
Read-only register: indicates which PLL reference is selected as the input to the PLL.
0: REF1 selected (or differential reference if in differential mode).
1: REF2 selected.
3
VCO frequency > Read-only register: indicates if the VCO frequency is greater than the threshold (see Table 16: REF1, REF2, and VCO
threshold
frequency status monitor).
0: VCO frequency is less than the threshold.
1: VCO frequency is greater than the threshold.
2
REF2 frequency > Read-only register: indicates if the frequency of the signal at REF2 is greater than the threshold frequency set by
threshold
Register 0x1A, Bit 6.
0: REF2 frequency is less than threshold frequency.
1: REF2 frequency is greater than threshold frequency.
1
REF1 frequency > Read-only register: indicates if the frequency of the signal at REF2 is greater than the threshold frequency
threshold
set by Register 0x01A, Bit 6.
0: REF1 frequency is less than threshold frequency.
1: REF1 frequency is greater than threshold frequency.
0
Digital lock detect Read-only register: digital lock detect.
0: PLL is not locked.
1: PLL is locked.
Rev. E | Page 65 of 80