Low-Ron N-Fet with no intrinsinc diode

[Santa]

low ron fet

I would like to know if anybody heared about a Fet that would have the following characteristics:

- N-channel enhancement FET
- low ON-state resistance (a few ohms maximum)
- NO intrinsinc diode so as to avoid the FET going into conduction when the drain becomes somewhat negative (say between 0 and -3V)

This is about like every N-Fet used as a swich but whithout the diode.
Is there a process that makes the existence of such a beast possible?

THX.

 

[unkarc]

low ron fets

Hi Santa,

It is not easy to find the kind of FET you need but the firm Calogic (and possibly one or two more) manufactures such types. It is the DMOS process for instance the SD404 type, see data sheet at their URL
**broken link removed**
This type includes Zener diode ESD protection between the Gate-Source but no diode is indicated between the Drain-Source. Unfortunately the indicated absolute maximum (reverse) Source-Drain voltage is 0.3V like most other MOSFets but maybe it is enough for you?
If not, there is the SD5000 series where 20V is indicated both for Drain-Source and Source-Drain voltages. But these are quad FET swich analog arrays, unfortunately with 20-70 Ohm ON resistances, depending on the Gate-Source switching voltage, see data sheet at **broken link removed**

Maybe there are other types from some other firms I am not aware of.
A google search may open up some more not so well known types.

regards, unkarc

 

[Santa]

low ron jfet

The CALOGIC fet also has a source-drain diode indicated by the arrow in the symbol. This is only a condensed representation of
the fet + diode couple. Hence the fact that Vds has also a limit of -0.3V.

As much as I know, the diode is a direct consequence of the process used to make these low Ron fets and appears between
the substrate, which is connected to one of the electrodes, and the other side of the channel.

I may be searching for a non-existent beast...

 

[uladz55]

low ron diodes

You can check Lovoltech Inc. Products

**broken link removed**

 

[MoonShine]

no of the n fet

Hi,

I think more info is needed; there are DMOS for RF apps from ST that don't include any ESD diode protection for Vds= 28V, 50V and 100V applications.

Of course there are some LDMOS products from ST that don't have any ESD diodes on the gate to ground.

Regards,
Brett