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# Bjt Lna

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26 Threads found on edaboard.com: Bjt Lna

## Area MOSFET for Power amplifier

Hello ! I am trying to design a power amplifier, I have a initial design aproach equations but this are for bjt, I am using mosfet and my doubt is for calculate the number of fingers I found these equation M=Idc/(Jemax*Ae device) (this equation is for bjt because is using Area of emitter) my question is what will be the equivalent for mosfet to

## Multi emitter BJT transistor

Hello there! Does anyone know if a multi emitter bjt would work as a regular one (1 emitter) if I shortcircuit all of the emitters' branch? I'm working with an oscillator and I just need a regular bjt but I have found a 2-emitter bjt that fits well with my needs. So, Should I shortcircuit the emitters or use only one of them? I have the (...)

## What's sets lower frequency limit of LNA devices?

BF862 is a JFET and is very good for your application. JFET's have much lower noise than any other transistor type (bjt, MOS, GaAs) at low frequencies.

## a negative voltage is added on a BJT's base

The reason of the negative bias is to increase the input/output isolation when the lna is in OFF state. In bjt this helps a little bit, but FET's provides better isolation in reverse bias state.

## LNA Collector inductor or resistor

Hello, I am attempting to design a lna with a bjt. Why would I use a collector bias resistor instead of a large collector inductor or LC parallel resonant circuit? The only advantages I can think of are: Resistor: 1. Gain over a larger bandwidth 2. Impedance matching would be easier over a broader range of frequencies. Inductor or pa

## common-base BJT LNA design

Hi all, happy new year! I have my first question this year. I am trying to understand how a common-base bjt lna works. The circuit I am analysing uses a transformer feedback. Does anyone know any literature, web site, articles about this type of amplifiers? Does anyone know what are the advantages of using this transformer feedback? Be

## the gps active antenna lna??

I see some vendor can supply the active antenna with 0.5dB NF of the lna and total NF with about 1.2dB, that's really good. Now , anyone can tell me which type lna component will be used in active antenna design?? use bjt or mos? can tell me detail???? thanks in advanced.

## Design of UHF/ Microwave Amplifier

the NEC3210S01 is a microwave one , he want to design a 600 MHz transistor , i recommend u one of NXP bjt low noise transistors u can get a very good lna with them in this range khouly

## SOME QUESTION ABOUT PTAT AND BANDGAP IN RF CIRCUITS

I know this is stupid question...but if I don't ask, I will be stupid not my question~~~ thank you first what I wanna ask is which circuit need a ptat current bias what circuit need bandgap I have seen that most rf lna use ptat why? (to compensate the bjt's negetive Vbe? this will increase the gm!!!) , but what if it is mixer or lo bu

## Why CMOS LNA is good as BJT LNA @ 2.4GHz

Because the inherent noise 4kTgm is higher than 2KTgm. But why the performance of cmos lna is also good?

## [Help] Improvement on LNA design

Linearity issue, my friend. If you do not degenerate the bjt you'll have signal compression for very low input amplitudes. Try to simulate with 1mV at SRC2 amplitude and you'll see the difference. I hope it can help. Mazz

## Why not to use the BJT as the device of LNA?

who said , that the bjt can't be used as lna , the noise figure of the bjt is much lower than the MOS , the gain of the bjt is much higher than the CMOS the linearity is lower than the MOS , i think bjt matching is harder but bjt till now used as lna , in the GHz (...)

## Where can I get a HEMT or BJT RF transistors samples?

I want to get some HEMT and/or bjt transistors for PA and lna application at 2.5GHz. Can some one suggest place(s) and transistors? Thanks in advnace, Ahmad,

## how can I control the flicker noise of bjt

usually I increase the size(w*l) of the mos to decrease the flicker but how can I do toward bjt for example emitter width and lengh....

## interview question on linearity

i guess in general linearity is traded with gain , bjt has higher hain so lower linearity

## Questions about mixer input impedence

if the mixer is bjt then the input impedance is Rpi and Cpi. So there is a resistor. if the mixer is a mos then the resistance is huge and there is also a cap, Cgate.

## active bias network for an LNA !!

i think you should make a match circuit. for a bjt,fet,hemt,it's match circuit perphaps different. for a certain impeadance match there have several sorts of method. for a 12Ghz frequency band,you should use a hemt or phemt,it have a good noise performance. bias circuit is not increase noise figure if you haven't a wideband demand. for

## How Ft & Fmax help to determin BJT size and supply curre

When designing lna and Mixer, how Ft and Fmax help to determin device size and supply current? What is the relation between gain, linearity and these figure of merit? Thanks

## looking for wideband lna manufacturer with uwb bandwidth

Hi there... If u are looking for the bjt u can used infineon or if u r looking for HEMT/JFET/PHEMT used for infineon u can apply for sample for education purpose but from filtronic i dunno... regards, shah

## When do we need Deep NWell in a BiCMOS process?

I need to choose a process with or without deep nwell. The process has deep trench and I will use the bjt for lna and mixer. Do we need the Deep NWell? Is deep nwell cost effective? Can I use the Deep NWell for the NPN? Which block needs deep nwell?