BF256B

[john_ellis]

Hi all
Farnell in UK have BF256B in stock if anyone is interested.

 

[U230421]

Farnell, RS, Distrelec and the rest have them all. A and C are rare. More curious about BF245A/B/C, way more subtle and suitable for audio applications.

 

[john_ellis]

That's as maybe. I preferred the BF244 with the "proper" pin out with centre gate. Both of those are made from unobtainium it seems, so would you rather have a BF256 or nothing?
Please support your statement about "subtle". What exaxctly does that mean? Transistors don't do subtle. The do have performance figures you might quote instead.

 

[altec9440]

Thanks for information.

often use this part as current source for led.

A sticky post may be usefull for becoming obsolete parts ?

 

[U230421]

Subtle in the way of transfer characteristic, like the mentioned BF244. The BF256 is more 'course' to put another statement. I do not refer to sonic qualities or otherwise.

 

[john_ellis]

Well, I'm still guessing what you mean by

Subtle in the way of transfer characteristic

.
I doubt very much you would see much difference in the transfer characteristics because the devices are built on the same process, and the "B" groups have pretty much the same Idss range.
Any more suggestions?

 

[john_ellis]

...the only differences which might be would be due to layout. If the 256 has a different W/L ratio to the 245/244 then I agree there would be a difference. But you could say "slightly higher gain" which explains things better than "subtle". However, in the IDss range this might not make a significant difference to actual performance.