Replacement for HexSense FETSs

Roger, The hex since can be replaced by using the standard IRFP250 and a parallel fet of higher voltage such as the IRFU420 with a 100 ohm resistor in the source. Connect both drains together and connect both gates together. The current signal is taken at the connection of the 100 ohm resistor and IRFU420. The other end of the 100 ohm resistor is connected to the source of the IRFP250. Also the fancy negative supply is not needed with this connection because there is no concern about the signal current being diverted in the silicon of the IRCP250. It also is more accurate with no distortion at higher currents. Ray

Thanks. What suprises me, is that nobody seems to integrate such a solution though, the 'dual fet' solution, will be rather bulkier (there are already eight FET's along the heatsink, and while only four need current sensing, it may get a bit 'tight'... :-) Have to find something other than the IRFU420 though. These too are 'divested'. Oh well, a 'redesigning I will go'!.

Best Wishes

I do not know the specific situation with this part, but just the fact that it is "divested" does not necessarily mean that you will not be able to get it in the future. Semiconductor companies have been selling product lines and splitting companies in the last few years. National Semiconductor, Motorola, HP, and others have done this over the last few years. It is just a matter of whether whoever ends up with the rights to your part chooses to produce it. I have been in several situations where I thought a key part was not going to be available due to this practice, but so far I have always been able to find it from some successor or partner of the original. (I am watching this particular situation myself as I use a number of IR parts.)

OK. Yes, I understand this practice (met it a lot, with TI parts in the past). The problem (of course), is that you have to 'assume the worst', unless the new manufacturer is already in place...

Best Wishes