Finding equivalent for a obselete FET

Thread Starter

Trapper John

Joined Oct 12, 2018
3
Hello all. Now that I've retired, I've got more time to devote to personal projects. I want to build a Phasing (Flanging) unit, but it uses old BF244B or BF245B FETS, and they don't make them any more. I've tried looking for equivalents, but I'm defeated by the description and/or absence of certain parameters between datasheets. Could anyone help please?

Thanks in advance
 

Thread Starter

Trapper John

Joined Oct 12, 2018
3
Dana - thanks for hat, but I came up with a similar BF545. The problem there is that it's an SMT/SOIC device, which I can't deal with. It has to be a wire-ended component, e.g. TO-92 package.
SamR - That looks a useful site, but suggesting an AD846 replaces a FET seems a bit odd! BTW, like the cat. Similar to one I had 20 years ago!
 

MrChips

Joined Oct 2, 2009
20,868
Generally speaking, I don't worry about exact equivalents when it comes to replacing BJTs.
I just look at basic parameters:

polarity
operating voltage and current
power handling
frequency
package

When it comes to FETs, same as above and in addition you have to look at depletion or enhancement.

Most of all, I use the circuit application as the guiding principle.
 
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