THS9000: S parameter

Hello Carlo,

I understand how having the data for return loss in the format of Figure 6 ( S21 vs R bias) would beneficial.   I am working on locating these 3V supply values for you.  If possible, I will also recommend any calculations to assist with approximating or understanding how R bias selection impacts return loss at 3V.

Best,

Alec Saebeler

Hello again Carlo,

I reviewed our documents and datasheet for the THS9000.  I will advise the S11 (return loss) parameter should not vary much (by any appreciable amount) due to various bias resistor selections.  The inclusion of a S21 vs. Rbias measurement but not an S11 companion measurement is intentional.  Of the suite of s-parameters measured, S21's variance over Rbias selection is the most critical to device function.  The provided S11 specs for 5V operation should provide good context and performance information for your customer's 3V supply case.  The THS9000 datasheet would suggest 3V operation to have negligible difference from S11 measured during 5V operation, due to the inclusion of only 5V curves. 

If your customer has a specific issue with their use of the THS9000 relating to 3V supply operation and bias resistor selection, I would be happy to assist your further on this thread.  Without any data or behavior to investigate, I have to recommend considering the information present on the datasheet.

If your customer is primarily concerned with those specs from a device selection standpoint and does not have any issues with use/testing, I would advise the customer to consider the provided datasheet measurements as sufficient characterization of the device.  Please reconnect with your customer and reach out again if you discover their need to grow/change.  I am also available via email.

I recognize there can be a disconnect between all the possible specifications a datasheet could contain vs. the specifications the datasheet actually contains.  In the case of the THS9000, I am comfortable advising you and your customer to refer to 5V S11 curves and consider S11 vs Rbias variation to be minimal.

Please reconnect and let me know if this resolves your issue.  If your customer has any additional data or measurement requests for this part, you may also inquire about those here.

Best,

Alec Saebeler

Hi Alec,


Thank you for looking into this. We appreciate it as well if you can share with us the calculations in Rbias selection.

Regards,
Carlo

Hi Carlo,

I will work on the calculations and get back to you with information on Rbias selection before the middle of next week.

Best,

Alec

Hi Alec, 

S-parameters are also important for stability and other analyses. Can you provide s-parameters as touchstone file for 3V and 5V supplies and different Rbias resistors or currents? 

Sincerely, 

ibrahim

Hi Ibrahim,

I will investigate retrieving and placing the information you requested into the S-parameter touchstone format.  I will reconnect and give an update next week; there may be some discussions I need to have with fellow team members.

Best,

Alec

Hello Ibrahim,

I am working with the team to verify a method for generating a good touchstone file.  I did create my own version using Excel and the typical s2p file header: # MHZ S DB R 50.  I also made sure to swap the data columns to fit S11 S21 S12 S22 format, versus the datasheet format.  We should have a file ready soon.

Alec