4 pin seperately controlled PowerMOS

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pianomania

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conventionally , we can get 3 pin PowerMOS at IR , fairchild, ...etc , that is the substrate will be short with source ,
where can we buy the individual POWER MOS which has D,G, S, B seperated ?

With it , we can do lot of experiement.
 

You won't hardly find any. In contrast to signal MOSFET, power MOSFET chip design doesn't allow to connect the bulk separately.
 

FvM said:
You won't hardly find any. In contrast to signal MOSFET, power MOSFET chip design doesn't allow to connect the bulk separately.
Click to expand...

what a pity , maybe it has no market!
 

pianomania said:
what a pity , maybe it has no market!
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No, this isn't the reason: a lot of people (like you and me ;-) ) would like to get them.
The real reason is - as FvM stated above - their design, or more concrete, their physical structure, which makes the parasitic reverse drain-bulk diode unavoidable.

Could you live with a junction FET? It doesn't own this diode.
 

pianomania said:
... where can we buy the individual POWER MOS which has D,G, S, B seperated ?

With it , we can do lot of experiement.
Click to expand...
Now I remember the rather old MC14007UB CMOS IC (from Motorola, now ON Semiconductor, but also available from other CMOS companies under the "4007" designation) which contains 3 n- and 3 p-MOSFETs, each 2 of them have their sources not connected to their bulks, hence are accessible as real 4-terminal MOSFETs. They are low-power devices (order of milliAmps), but might be sufficient for some experiments.

These CMOS ICs are still available on the market.
 

I explicitely wrote about power MOSFET, because I know, that a lot signal MOSFET with separate bulk terminal is available. I've been using them occasionally in special analog circuits, e.g. Vishay (former Siliconix) SD2xx family. CD4007, as mentioned by erikl, has separate bulk connection, but also various parasitic elements, e.g. substrate diodes, that may be unsuitable for an application.
 

FvM said:
CD4007, ... , has separate bulk connection, but also various parasitic elements, e.g. substrate diodes, that may be unsuitable for an application.
Click to expand...
For sure: the parasitic source-bulk & drain-bulk diodes aren't preventable due to the very construction of MOSFETs, and this is the same for the Siliconix SD2xx family, s. its dataSheet (Drain-Body Breakdown Voltage).
 

drain-bulk diodes aren't preventable due to the very construction of MOSFETs
Click to expand...
Right, but CD4007 has much more diodes and protection elements.
 

FvM said:
Right, but CD4007 has much more diodes and protection elements.
Click to expand...
Very true: 2 parasitic diodes for any of the 6 MOSFETs, i.e. 12 in total ;-) . No further protection elements, as the SD2xx series has (gate-to-body protection).
 

FvM said:
I meant the series resistors.
Click to expand...
I see: the input protection resistor of the 4000 CMOS series. This one possibly doesn't exist in the SD2xx MOSFETs, because they use a different input protection scheme.
 

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