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Inductance lead effects - RF Cafe Forums

Because of the high maintenance needed to monitor and filter spammers from the RF Cafe Forums, I decided that it would be best to just archive the pages to make all the good information posted in the past available for review. It is unfortunate that the scumbags of the world ruin an otherwise useful venue for people wanting to exchanged useful ideas and views. It seems that the more formal social media like Facebook pretty much dominate this kind of venue anymore anyway, so if you would like to post something on RF Cafe's Facebook page, please do.

Below are all of the forum threads, including all the responses to the original posts.


Jeanalmira
Post subject: Inductance lead effects Posted: Fri Sep 09, 2005 3:59 am
 
General


Joined: Tue Mar 15, 2005 11:43 pm
Posts: 65
Location: Singapore
I'm currently designing 3.5GHz power amplifier module, with the clip pin lead. I'm wondering whether the inductance of the lead (especially output lead) will significantly affect the performance?

and also due to the substrate thickness, the lead will be bent to connect to evaluation board (jig). So, there'll be gaps in between. I'm not sure whether it'll affect the performance especially at 3.5GHz range?

I've done some simulation by adding some inductance at the output. The gain is not significantly affected, but there's some effect at output return loss ( although not "high" ). Since so far, I only be able to do small signal simulation, I'm worried that it'll affect power performance at the end.

Could anybody kindly advise me how to do the "right and accurate" simulations to observe/ predict the effects on overall performance?
I need to prepare some anaylsis before send to fabrication.

Your advice is much appreciated.

Thanks and Regards,.
Jean


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IR
Post subject: Posted: Fri Sep 09, 2005 9:03 am

Site Admin


Joined: Mon Jun 27, 2005 2:02 pm
Posts: 373
Location: Germany
Hello Jean,

I didn't understand compleltly from your description what is a clip pin lead

Could you tell what is the package type?

If you mean that there is an air gap between one pin of yor active device to the substrate this will certainly cause a discontinuity in the impedance and will affect your return loss. If this occurs at the output it could be worse, because as you may know, the output is much more dominant in PA design.

I think that you can simulate an air-gap by measuring the dimensions of the air-gap and add a shape(s) of transmission line(s) with the same dimensions that has a dielectric coefficient of Er=1 (Dielectric coefficient of air).

Please provide the information above so I can help you more.

_________________
Best regards,

- IR



Posted  11/12/2012
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