How to adjust the Vgs of the PA in ADTR1107?

The ADTR1107 has supply sequencing requirements which when connected to the ADAR1000 require the use to also program and enable the PA_BIASx to -2.5V before bringing up the +5V VDD for the ADTR1107.  

Please see the ADAR1000 AND ADTR1107 section in the datasheet starting on Page 44 for more details on what the exact supply and programming sequence.  "Setting the ADAR1000 PA_BIASx Pins" on page 45 details exactly what bits need to be set in which registers. 

Please read the entirety of pages 44 and 45 in the datasheet for details & instructions on supply sequencing and programming of the switch bias, PA bias and the LNA bias pins.

Thanks for your answer. I have carefully read pages 44 and 45 of the ADAR1000 datasheet.

Should I expect the PA current of each ADTR1107 to be 220 mA if Vgs=-1.1V, or may we have significant current variation from part to part?

What I mean is that if the current varies noticeably between samples, it may be necessary to fine-tune Vgs so that all PAs have the same current. According to the diagram above, the ADAR1000 does not sense the current of the ADTR1107, so I am wondering how can I do the fine tuning of Vgs.

I don't know what the Idq spread is for the ADTR1107 PA.  Hopefully Jim Bedrosian can answer that. 

You would need a power monitoring part like the LTC2992 to sense each PA's current, feed that information back to the ADAR1000, and adjust the ON values of the PA_BIAS pins.

Hi Andresmmera,

                               I am working on getting the VGG distributions for the ADTR1107 Tx.

Regards,

Jim B

Thanks a lot, Jim.

Hi Andresmmera,

                                 Attached is the VGG, IGG and Idq distribution for the ADTR1107 Tx amp. 

Regards,

Jim B

PDF

Him Jim,

Thanks for the stats! That's really nice.

Just to check, does N here mean the number of samples?

Thank you again, I really appreciate it.

Correct, 12412 is the number of samples.

Correct, 12412 is the number of samples.

Hi,

I believe that the question has already been answered so I am closing this thread. Thank you!

Regards,
Paul