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How does MOSFET connect body to source or ground?
In most applications this body terminal must be kept at a potential that guarantees that the drain-body and source-body diodes are kept reverse-biased so that the device can function as a FET. In most cases this can be guaranteed by connecting the body junction to the source, this creates a reverse-polarized drain-source diode.
How are FETs connected to a different potential?
Connecting the substrate node of such FETs to a different potential, means that the wells have to be kept separated by relatively large distances (the related parasitic devices could destroy the IC otherwise) and that different well contact regions have to be provided.
How is the substrate connected to the FETs?
In other power applications, such as battery-backup circuitry where reverse polarities are normal, the substrate is actually connected to the effective drain terminal of the FETs. However, in most IC technologies the substrate itself is the body of the integrated FETs.
Why do we need a body terminal in a FET?
E.g., as a lower-gain input to increase the linear range of the circuitry. In most applications this body terminal must be kept at a potential that guarantees that the drain-body and source-body diodes are kept reverse-biased so that the device can function as a FET.
Why is the substrate in NMOS connected to ground?
We don’t try to reverse bias the substrate,body or bulk or channel.But,the junctions at source and drain reverse biased with respect to substrate such their is no loss of current into substrate that is the reason why we connect NMOS to ground and PMOS to vdd. Same as above, but will try to present differently to get more understanding.
How are NFETs kept reverse polarized in an IC?
This means that there is only one substrate node for all of the NFETs in the the whole IC. The only way to ensure that the NFET diodes are kept reverse-polarized is to connect the substrate of the IC to the lowest potential in the whole circuit.