What is the Effect of Floating MOSFET Base Plate?

AI Thread Summary
Leaving a MOSFET base plate floating can lead to potential issues such as voltage breakdown and electrostatic discharge (ESD) risks, as the substrate is typically connected to the source terminal for safety and isolation. The voltage acquired by a floating base plate depends on the specific device and its application, making it crucial to consider circuit design. It is common for the base plate to be connected to the drain, which complicates the notion of it being truly floating. To assess the implications of a floating base plate, detailed information like a schematic and part number is necessary. Understanding these factors is essential for ensuring circuit reliability and performance.
EE4me
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Are there any downsides to leaving a MOSFET base plate floating?
My specific system will benefit from having the MOSFET base plate floating. Are there any downsides to leaving a MOSFET base plate floating? Are there any reasons not to?
 
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EE4me said:
Are there any downsides to leaving a MOSFET base plate floating?
Base plate ? = body ? substrate ?
It is usual to connect the substrate to the source terminal so as to prevent voltage breakdown, ESD, and to maintain isolation by reverse biasing the PN contact layer on the substrate.
What voltage will it acquire if it is left to float ?
https://en.wikipedia.org/wiki/MOSFET#Body_effect
 
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This depends on the specific device and the circuit/application. Usually the "base plate" is connected to the drain, so it won't be truly floating. You won't get a useful answer from us without providing more information. You could start with a schematic, the part number of the MOSFET, and a description of what you want your circuit to do.
 

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