Isolation barrier in digital signal isolator.

Alex_bam

New Member

• Apr 6, 2022

• #1

Hello,

Could anyone comment on why a capacitor is better than an inductor according to the statement below:

"In general, an isolation barrier implemented with capacitors is better for passing signals to low impedance nodes than a barrier formed from inductors."
source: https://patentimages.storage.googleapis.com/8a/f0/44/e4b751f0ae6805/US7923710.pdf
Thanks.

 

S

schmitt trigger

Well-Known Member

Most Helpful Member

• Apr 6, 2022

• #2

An isolation barrier utilizing magnetic components must use a transformer, not an inductor.
For the simple reason that an inductor at DC or power line frequencies, is essentially a wire. Not much isolation here.

 

ronsimpson

Well-Known Member

Most Helpful Member

• Apr 6, 2022

• #3

The people that make transformer isolated parts think theirs are better.
The people that make capacitor isolated parts think theirs are better.
The people that make light isolated parts think theirs are better.

IMO ronsimpson

 

crutschow

Well-Known Member

Most Helpful Member

• Apr 6, 2022

• #4

Rather than being concerned about how the isolation is done, look at the specifications for the isolation devices, and see which is better for your application.

 

P

Pommie

Well-Known Member

Most Helpful Member

• Apr 7, 2022

• #5

Digital signals are almost always isolated using an opto (isolator) device.

Mike.

 

unclejed613

Well-Known Member

Most Helpful Member

• Apr 8, 2022

• #6

the OP is looking for isolation on a silicon chip. capacitors are better on silicon because they are simpler to make. transformers are very difficult to make on silicon.