Any info to point to on doing Phase Modulation with our PLLs (Note that ADF4158 says it is supported, but it is prelim, with no datasheet).
One difficulty with the ADF4350 as a PSK modulator is that it is not possible to disable band-select, meaning that the phase and frequency vary widely with each update to R0.
On the upcoming ADF4351, it will be possible to update the output phase without the need for band select, so this is likely to be more suitable as a PSK modulator.
from ADI PLLs only ADF4158 is capable of performing PSK modulation. You only need to select appropriate bit in software to activate PSK and apply data to TXdata Pin. 0 - corresponds to phase = 0 and 1 corresponds to phase = 180. Data signal applied to TXdata Pin should be within voltage limits specified for logic inputs in the datasheet.
It is also possible to perform PSK modulation on the ADF4350 using the phase control bits and the phase resync feature.
The phase resync applies a reset to the output phase after a programmable delay to ensure consistent phase each time you update the phase.This delay will limit the maximum PSK bit-rate that is achievable to a couple of kbps. However it means you can implement a compact PSK modulator using a PLL only, without the need for an DAC + I/Q modulator.
WHEN this ADF4351 will come available?
We was trying ADF4350 for wideband, fast switching equipment and our's hope connected with chip is failed.
We anticipate general availibility in the late spring of next year.
How much this chip will be faster over ADF4350?
I'm asking about internal VCO switch/setup time.
Will this new chip be pin compatible to the ADF4350?
The final settling time will depend on the loop filter. But the VCO band switching time should decrease from 80 us to 10 us.
I should add that the part will be pin and software compatible.
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