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
Messages
17
Reaction score
1
TL;DR Summary
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?
 
Engineering news on Phys.org
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
 
Last edited:
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.
 
I have recently moved into a new (rather ancient) house and had a few trips of my Residual Current breaker. I dug out my old Socket tester which tell me the three pins are correct. But then the Red warning light tells me my socket(s) fail the loop test. I never had this before but my last house had an overhead supply with no Earth from the company. The tester said "get this checked" and the man said the (high but not ridiculous) earth resistance was acceptable. I stuck a new copper earth...
Thread 'Electromagnet magnetic field issue'
Hi Guys We are a bunch a mechanical engineers trying to build a simple electromagnet. Our design is based on a very similar magnet. However, our version is about 10 times less magnetic and we are wondering why. Our coil has exactly same length, same number of layers and turns. What is possibly wrong? PIN and bracket are made of iron and are in electrical contact, exactly like the reference design. Any help will be appreciated. Thanks. edit: even same wire diameter and coil was wounded by a...
Thread 'Beauty of old electrical and measuring things, etc.'
Even as a kid, I saw beauty in old devices. That made me want to understand how they worked. I had lots of old things that I keep and now reviving. Old things need to work to see the beauty. Here's what I've done so far. Two views of the gadgets shelves and my small work space: Here's a close up look at the meters, gauges and other measuring things: This is what I think of as surface-mount electrical components and wiring. The components are very old and shows how...
Back
Top