Timeline for Why reverse connected MOSFET start to turn on at Vgs<Vth?
Current License: CC BY-SA 4.0
21 events
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| Aug 26, 2019 at 20:44 | comment | added | Russell McMahon♦ | I think that Silicon on insulator devices do not have an intrinsic body diode - eg Silicon on Sapphire. This process is not usually used in discrete devices but is the basis for some IC processes. From memory the aim is increased speed at the expense of increased cost. | |
| Aug 25, 2019 at 17:39 | comment | added | Elliot Alderson | @G36 The incorrect statement was made about "every MOSFET", not about the AO3400 specifically so it doesn't matter how that particular device is constructed. | |
| Aug 25, 2019 at 17:35 | comment | added | Elliot Alderson | @G36 The definition of "MOSFET" does not depend on your ability to purchase one. In any event, see digikey.com/product-detail/en/microchip-technology/… and electronics.stackexchange.com/questions/137161/… | |
| Aug 25, 2019 at 17:25 | comment | added | G36 | @ElliotAlderson I know that. But I asked for an example of a 4-terminal MOSFET's that I can buy? Also, notice that AO3400 is a vertical device. | |
| Aug 25, 2019 at 17:21 | comment | added | Elliot Alderson | @G36 The diagram at the top of the Wikipedia MOSFET page shows a 4-terminal MOSFET, If you read the "Analog Switch" section it talks about "drain and source of a MOSFET exchange places" and "uses a four-terminal simple MOSFET". | |
| Aug 25, 2019 at 17:04 | comment | added | G36 | @ElliotAlderson Any example? | |
| Aug 25, 2019 at 16:58 | comment | added | Elliot Alderson | Your first statement is not true. There are 4-terminal MOSFETs that do not have a diode from source to drain. | |
| Aug 25, 2019 at 16:18 | comment | added | ssa2 | Then, I wait for semiconductor physist, thank you. | |
| Aug 25, 2019 at 16:15 | comment | added | ssa2 | But , when we think about beginning voltage of conduction, can we think with on-state? | |
| Aug 25, 2019 at 16:07 | comment | added | G36 | The on-state characteristics of a MOSFET are symmetric. And simply now the drain act as a source and source as a drain. Why it is true I don't know. You need to ask about it semiconductor physicist | |
| Aug 25, 2019 at 15:58 | comment | added | ssa2 | ＞I think it is ... This is about the graph of reverse one. | |
| Aug 25, 2019 at 15:30 | comment | added | ssa2 | Oh, this result represents MOSFET can be turned on by Vgd, not only by Vgs. Why? Source and Body is connected, so Vgs=Vgb then chanel is appear, but drain is not connected to body ,so Vgd can't apply voltage between gate and body. Why Vgd can turn on MOSFET? | |
| Aug 25, 2019 at 15:25 | comment | added | ssa2 | I think it is Vgd-Vds graph, not Vgs-Vds. | |
| Aug 25, 2019 at 15:16 | comment | added | G36 | See my graph from LTspice. | |
| Aug 25, 2019 at 15:15 | history | edited | G36 | CC BY-SA 4.0 |
added 193 characters in body
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| Aug 25, 2019 at 15:13 | comment | added | ssa2 | Yes. I got it from website | |
| Aug 25, 2019 at 15:12 | comment | added | G36 | Do you have a MODEL for AO3400? | |
| Aug 25, 2019 at 15:03 | comment | added | ssa2 | But Vds is start to drop down at 0.5V even though Vgs is far from Vth. | |
| Aug 25, 2019 at 15:00 | comment | added | G36 | @Sano Until V2 voltage is lower than Vht the bod diode is ON and conduct current. Right? But at the time when V2 > Vth MOSFET normal (channel) current begins to flow. And MOSFET shorts out the diode current. | |
| Aug 25, 2019 at 14:51 | comment | added | ssa2 | I know it, and it is written in my question. I want to know why reverse connected one is start to drop down Vds when Vgs is under Vth.(near 0.5V) | |
| Aug 25, 2019 at 14:46 | history | answered | G36 | CC BY-SA 4.0 |