Does the ADF4351 support operation as a VCO only by utilizing the charge pump tri-state and counter reset bits, similar to the ADF4350?
Yes - it's pretty much identical in this application.
You can use ADF4351 instead of ADF4350 for CN0232. CN0232: http://www.analog.com/en/design-center/reference-designs/hardware-reference-design/circuits-from-the-lab/cn0232.html#rd-overview
Thanks. For some reason after I get my PLL to lock and I turn on counter reset in the 4351, the VCO turns off.
Are the following the instructions exactly as in CN0232?
When you write the ADF4351 register, are you writing all registers, or just the changed one?
Yes, we are, though we are not using the ADI software.
When we write the ADF4351 register we are only writing the changed register.
Counter reset should not power down the VCO (or anything else for that matter).
I will check a part out just to be sure, but the 4351 has almost identical functionality (plus a few extras) with the 4350. The ADF4355 counter reset puts the part into a power up state, but not the 4351.
Update: Just checked the ADF4351 with an evaluation board and the evaluation board software.
You could clearly see the VCO signal at the original frequency slowly drifting away, after the counters were placed in reset. This tells me that the function is working correctly.
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