1700-1900MHz 20w RF amp - RF Cafe Forums

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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

Posted 11/12/2012