Which is the lowest noise FET?

[Young]

Hi everyone!

Does anybody have a thorough comparison of the noise level between various FETs?

I am looking for a FET with the lowest noise, low current (<1mA), low voltage (<=3.3V), and surface mount package. I want to use it as the first stage of my amplifier.

The old 2SK170 and 2SK369 seem to be out. I searched at Toshiba home site, but there is no list there.

There are a number of Op Amps out there, but they are not what I am looking for.

Thanks for any responses.

Best regards, Young

 

[mlloyd1]

look for a company called InterFET at www.interfet.com

unless you manage to get a sample or two, be prepared to spend $$

mlloyd1

 

[lineup]

look for a company called InterFET at www.interfet.com

unless you manage to get a sample or two, be prepared to spend $$

mlloyd1

You can download InterFET 'Whole databook' ( I did! )
it is a 189 pages PDF with data of their JFET:
http://www.interfet.com/jfet.htm

Also you can request this paper from InterFET:

Methods of Reducing Noise of Junction Field
Effect Transistor (JFET) Amplifiers
H. E. Kern, J. M. McKenzie (Bell Telephone
Laboratories, Inc.)

 

[Bensen]

Hi,

Three months ago I ordered 6 x 2SK389BL and 6x 2SJ109BL FET's at:

http://www.donberg.ie/


Greetz
Ben

 

[atarashi]

As the Toshibas are out, Interfet would be one choice, but at least in Europe not easy to come by...

So what remains?

Something like BF 998, BFR 30/BFR 31, but i have no idea how they sound?
At least they are low noise...

Regards
Michael

 

[jackinnj]

you might be able to get some samples from Linear Systems -- they advertise in AudioXpress (which is a good sign) but they don't have a typical distributor like Mouser or DK: www.linearsystems.com --

I have some TO-92 (non-surface mount): http://www.tech-diy.com/smallsignal.htm if you get stuck.

 

[lineup]

you should be able to find 2SK170 and 2SK389 in Europe
no problem
do some search for electronic components providers

for example at www.dalbani.co.uk
http://www.dalbani.co.uk/electronic_components/transistors.php?p=41|

 

[genome]

interFET does have LSK389 (= 2SK389).
But they do not have 2SJ109.

 

[Young]

Thanks, but my question is which is the best!

I suspect there must be a reason that Toshiba took those FETs out, and they should have been replaced by some better ones.

170 and 369 are not SMD. Let me tell you a secret: according to my experiments, SMD has much better performance than TO-92! My interpretation is the leads are much shorter!

Thanks again, Young

 

[jcx]

if en in jfets is ~ porportional to 1/sqrt(gate area) then these should win:

http://www.lovoltech.com/pdf/LD1014D.pdf

of course the 1/f corner may be anywhere as they really won't be tracking on obscure process dependencies for pwm switches

anyone try for a noise measurement of these (pass forum?)

"best" is as usual contex/application/system dependent, Power Amp w/line input?, mc pre? what do you really need?

 

[Young]

if en in jfets is ~ porportional to 1/sqrt(gate area) then these should win:

http://www.lovoltech.com/pdf/LD1014D.pdf

of course the 1/f corner may be anywhere as they really won't be tracking on obscure process dependencies for pwm switches

anyone try for a noise measurement of these (pass forum?)

"best" is as usual contex/application/system dependent, Power Amp w/line input?, mc pre? what do you really need?

Thanks. Since I am looking for the first / pre stage with small signal (uV), the "best" is defined by the lowest noise level in the low frequency (DC - 40kHz) range. However, various FETs got various features, and so users may have used different FETs, based on their preference and experiments. I would like to see what people think and why they made such a choice.

Thanks! Young