Hello.I want to replace a BF245A with BF244A in a constant current source. Are drain and source pins of BF244A interchangeable?Looking at the datasheet of BF245A it says that they are interchangeable but i couldnt find any info for BF244A..
Most J-FET's are 100% symmetrical and the D-S markings have little relevance in practice. The late Bob Pease once told me that you identify them by talking to it 😉 and saying you are the drain and you are the source. Its always worked for me.
For GP devices, switches, etc, jFets are normally symetrical, but there are some subtleties: even if the chip itself is completely symetrical, the pinout lends it to a particular application: for example, if the gate has the middle position the device is better suited to common-gate applications.
For VHF/UHF or ultra-low leakage devices, the symetry is often already lost at the chip level, because of guardings, metallizations, areas or order of respective terminals, etc.
For VHF/UHF or ultra-low leakage devices, the symetry is often already lost at the chip level, because of guardings, metallizations, areas or order of respective terminals, etc.
Sounds like imprinting for the first time.
What if you later take it out to different circuit and you accidentaly flip it.
Will it remember and refuse to work?
🙂
Back when the Intersil/Siliconix databook showed the die, everything was usually symmetrical.
If there is a difference in bond wire lengths, the shortest one makes the best source at RF
If there is a difference in bond wire lengths, the shortest one makes the best source at RF
They have no memory, as soon as they are removed they forget what was spoken to them and they are happy to be told different next time 😀
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