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1700-1900MHz 20w RF amp - 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.


SDO
Post subject: 1700-1900MHz 20w RF amp Posted: Thu Jan 15, 2009 4:55 pm

Captain


Joined: Tue Aug 26, 2008 5:18 am
Posts: 22
Location: UK
Hi,
can any one advise me which transistors are available for designing 20w, 24-28V balanced RF amp to cover 1.7-1.9GHz band. I am using Microwave Office so it will be nice to have a device whose model is available in MWO like freescale.
Thanks.
SDO


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IR
Post subject: Re: 1700-1900MHz 20w RF ampPosted: Fri Jan 30, 2009 5:10 pm

Site Admin


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

Take a look at Infineon line of RF Power Transistors.

http://www.infineon.com/cms/en/product/ ... Power.html

From recent experience with them, I know they also have models for MWO.

Good lcuk!

_________________
Best regards,

- IR


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SDO
Post subject: Re: 1700-1900MHz 20w RF ampPosted: Thu Feb 19, 2009 6:47 am

Captain


Joined: Tue Aug 26, 2008 5:18 am
Posts: 22
Location: UK
Hi IR,
Thanks for your reply. I've designed 20W PA (balanced Class A) operating from 1700MHz to 1900MHz using MRF19030 Transistors from Freescale.
Regards.

SDO


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FSomma
Post subject: Re: 1700-1900MHz 20w RF ampPosted: Mon Mar 30, 2009 4:52 pm
Hello SDO,

Just to add some thoughts to your selection:

-The MRF19030 transistor form Freescale might be obsolete or in the way, perhaps you want to take a look to the Freescale 5th or 6th generation LDMOS amplifiers (MRF5... MRF6...) they are more efficient and rough (difficult to burn by a fair output load).
Also, you asked for a Class A operation, these Freescale transistors were designed to work as Class AB... I think if you try to make it work into a Class A operation you might end up having a lower P1dB.

-A 30W transistor for 20W sound like a good choice from the fact that you will have to use a very broad band match (many match stages---> more insertion loss) to meet the specs from 1.7 to 1.9GHz.

-Remember to add a circuit to compensate the bias point drift over temperature, specially if you plan to use it in a high bias point where you will have a lot of heat generation ( I assumed this from the fact that you asked for a class A amp) .

Take care








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