LMX2820: LMX2820 doubler manual calibration

Hi Mikhail,

Let me check with the designer and get back.

Good day Noel,

Thank you! Will be waiting news.

Mikhail

Good day Noel,

could you tell me if you got any news for me?

thank you, Mikhail

Hi Mikhail,

Not yet, I will push again.

Good day Noel,

Sorry for pushing, any update for me?

Thank you, Mike

Hi Mikhail,

I just aware that because of Diwali, the designers are taking time off, I am afraid I may not have the answer by this week. I will let you know once I've got the answer. 

Good day Noel,

could you tell me if you got any news?

Thank you, Mikhail

Hi Mikhail,

yes finally...

Yes, we can readback the doubler calibration data as well similar to the VCO calibration data.

But to apply this data manually , we have to write 7 different fields(spread across  3-4 registers)  along with 7 different overrides.

So, technically speaking, we can read back those information. Our question is, we do not need to know these values as Instant Calibration will do it for us. Instant calibration will gather all the calibration data and apply it automatically so that we can get very short frequency switching time. If we apply these data manually, we need to spend some time in programming so eventually the overall programming + frequency switching time will be longer. 

Can the customer use instant calibration instead of manual programming?

Good day Noel,

Thank you very much for answering me.

Any chance to get a manual how to perform the manual calibration?

customer would like to compare a time needed for this procedure. As the time is very critical to him.

Thank you, Mikhail

Hello Mikhail,

Does the customer have a time spec?

73,
Timothy

Good day Timothy,

Customer is saying, a time he calculated starting from loading of the R0(DBLR_CAL_EN=1; FCAL_EN=0) register is 30 usec for doubler calibration.

in his experiment, VCO was calibrated already.

A time is very critical for the customer. Maybe you can suggest the best and shortest way for this procedure?

Thank you for helping!

88,

Mikhail

Hi Mikhail,

It is still not clear to me why the customer needs manually write doubler calibration codes. Write R0(DBLR_CAL_EN=1; FCAL_EN=0) means we want to perform a vco doubler calibration only. Does that mean the customer is already at fo, now he wants 2 x fo, so he programs OUT_MUX to "VCO doubler" and then program R0 to calibrate vco doubler?

During the one-time Instant Calibration process, both VCO and VCO doubler will be calibrated. When we enable the VCO doubler, we don't need to calibrate the doubler again.

Just want to make it clear that VCO doubler calibration actually means tracking filter calibration. The tracking filter is used to reduce the fundamental VCO signal when VCO doubler is enabled. As such, the doubler calibration is optional if the level of the fundamental VCO signal is acceptable.