Some other Source Follower Configurations

[EUVL]

You can always buy them from ebay for 10 USD for two :
https://www.ebay.com/p/2SK209-Original-Toshiba-MOSFET/1101801903

Or buy 300 from Chip1stop and sell the surplus on ebay for the same price above.

> I know your time is probably worth much more than 40$ ....

That is about 10 minutes worth of my time at work.


Patrick

 

[JPS64]

https://ciiva.com/part/2sk209-grte85l-f-4870691

https://ciiva.com/part/2sk209-blte85l-f-3015843

JP

 

[RCruz]

I am surely interested in the BL version.

 

[kinku]

JP it is not accurate , if you click mouser and digikey links it will say zero available or you have to buy 3000!

 

[JPS64]

https://www.questcomp.com/QuestDeta...m_medium=industry-cpc&utm_campaign=partsearch

You´re right, sorry.

JP

 

[kinku]

JP it is not accurate , if you click mouser and digikey links it will say zero available for BL ,or you have to buy 3000!

Don't trust other resellers found in Google .

 

[JPS64]

ok, will ask my purchasing department if we can buy small quantites at Avnet Europe.

JP

 

[kinku]

That will be awesome , like Patrick suggested should do a group buy if there is enough interest.

 

[EUVL]

You need to match anyway.
So anything < 100 does not make sense.


Patrick

 

[JPS64]

sorry, only order >= 3000, Avnet and others.

Patrick, what´s the rate if matching?

JP

 

[EUVL]

You guys are wasting time discussing 40 USD, including free delivery to the US.
3 persons, 14 USD each, what is the problem ?

MoQ from Mouser or DK is more.


Patrick

 

[kinku]

Patrick , you got it wrong, I am afraid.Mouser don't have it. Digikey won't sell it less than 3000 at 20cents per piece that is 600$. The 40$ is just for shipping from other source excluding device price to US from Japan. I had better luck matching BF862 close to 1% IDSs with just 10-15. I got one exact match in 20 with ID and Vp.BF 862 is much more easier to source too.

 

[EUVL]

Two more configurations and compared to a simple source follower with the same devices.
Feel free to try others.


Patrick

.

 

[kinku]

Dear Patrick, is there anyway you can make one for Bf862 too please....!

 

[EUVL]

LT Spice exercise for you.


Patrick

 

[kinku]

One that I know would fail miserably , master!

 

[Nelson Pass]

A quick look at the curves, you can expect something like 0.01% thd or less
at 1 V out using it as a current sourced follower.

I would use them myself if my eyesight was good enough....

 

[kinku]

BF862 or the the circuit above Papa?

 

[kinku]

Patrick, I vaguely remember somewhere you explained the preference of K209 over BF862. I looked at noise levels one is in dB and other is in nV/ Root Hz so could not compare. In general BF862 is considered not an audio FET and made for RF use , is it the reason?

 

[Nelson Pass]

BF862 or the the circuit above Papa?

It don't currently have LTSpice installed on this machine, so I have not
seen the schematic. Rather I compared the curves of the BF862 relative
to a 2SK170 in a follower using two such transistors, one as a constant
current source and the other the follower.

The 2SK209 looks like a nice part, but I would be selecting for Idss > 6 mA
for a follower.