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Choice of the foundry

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APPUARPITA

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Dear All,

I am planning to design a LNA (12-18 GHZ) and an active multiplier in this band in MMIC ,can anybody let me know what are the foundry parameters i have to choose before start of the design ?

What Ft will be the best for this range ? Any other parameter can i have to choose?, please help me in choosing the best GaAs process.
Is very high Ft is advisible ?
i want in my design single supply, ( to avoid sequential bias supply), can i use enhancement mode type device ?, instead of depletion mode device ?
can anybody tell me what are the advantages and disadvantages of both types of devices.

please guide me.
 

You don't have so many choices in term of Foundry but ask that question first to yourself: What is my budget ??
Because GaAs processes are pretty expensive ones and there are many variants at a Foundry.
QORVO and WIN Semiconductors are well known commercially available Foundries but there are some others which are not open to commercial customers such as Rockwell,TWT etc.( they're working for military projects and accessing to their foundries is not easy due to export policies and restrictions)
Every process has positive and negative points and they should be carefully examined by requesting measured and modeled specifications.And it takes time to examine all..
 
Depending on technology and circuit you may care more
about fT or fMax. Depends on what kind of gain (voltage
or power). RF is usually in terms of power gain and fMax
(as I make it out, from hanging out - not a "radio dude").

If you want a gain of 10 then your fWhatever needs to
be 10X the operating frequency at a minimum (there
are other detractors in any circuit, besides the active
amplification device itself).

Power level will probably determine which GaAs flow, or
GaN. I've seen 3.5V and heard about 8-9V GaAs (the 3.5V
was the TX supply on X-band phased array radars I did
element control chips for). Per-element power on those
was low-ish, more power in a 50-ohm system needs the
higher voltage (which probably means lower frequency)
technology.
 
Sir,

Then can i say Fmax is the major parameter ?I got a quotation of two foundries one is having Ft= 60GHz and other is Ft=90GHz, which one shall i choose ?Any other parameter can also i have to consider ?
My frequency of operation is 12-18GHz, Can i use HBT instead of PHEMT?

In some of the readily available products i have seen gain amplifiers of single supply and the manufacturer is telling the device used in design is enhancement mode type instead of depletion mode , where gate and drain has to bias sequentially..
how to comapare enhancement mode device over depletion mode device !
Thank you.
 

Sir,

Then can i say Fmax is the major parameter ?I got a quotation of two foundries one is having Ft= 60GHz and other is Ft=90GHz, which one shall i choose ?Any other parameter can also i have to consider ?
My frequency of operation is 12-18GHz, Can i use HBT instead of PHEMT?

In some of the readily available products i have seen gain amplifiers of single supply and the manufacturer is telling the device used in design is enhancement mode type instead of depletion mode , where gate and drain has to bias sequentially..
how to comapare enhancement mode device over depletion mode device !
Thank you.

Look at NF values @12-18GHz because NF is more important than fT.
Depletion Mode pHEMTS have lower Gm but more linear.( they need also negative bias voltage)
Enhancement pHEMT have higher Gm but less linear.( more sensitive to bias voltage variations.
HBTs are generally not used Low Noise applications but I don't know recent developments.
 
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