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Design >> Analog Design >> Breakdown Voltage Diode
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Message started by bki on May 5^th, 2015, 5:25am

Title: Breakdown Voltage Diode
Post by bki on May 5^th, 2015, 5:25am

The breakdown voltage of a Diode is 50V.

So, if i add 150V to one terminal of the Diode and 190V to the other terminal of the Diode, the voltage drop across the Diode is 40V.
Is that ok for the Diode then or is it already a Problem that the voltage on the individual terminals are so high (150V/190V) ?

Title: Re: Breakdown Voltage Diode
Post by loose-electron on May 5^th, 2015, 10:13am

for a discrete diode in a separate package (not integrated into an IC)
the relative voltage (difference between the two connections) is all that matters

Title: Re: Breakdown Voltage Diode
Post by bki on May 6^th, 2015, 2:00am

and how is the case for an integrated Diode?

Title: Re: Breakdown Voltage Diode
Post by carlgrace on May 6^th, 2015, 1:10pm

bki wrote on May 6^th, 2015, 2:00am:

and how is the case for an integrated Diode?

It's the same in principle, but can be quite different in practice. You can run an IC off whatever voltages you wish, as long as the difference between the voltages you define as VDD and VSS is within allowed limits.

The challenge here is that typically an IC is connected to a ground plane on a PCB so now instead of just a diode operating at elevated voltages you have a whole system floating. That can lead you to a whole world of hurt regarding proper grounding and EMI considerations (and that's just for starters). People do this, but you have to think it through.

Title: Re: Breakdown Voltage Diode
Post by loose-electron on May 8^th, 2015, 4:27pm

integrated diodes are actually multiple diodes in one package. You have the parasitic diodes (to substrate and things around the diode) to also be concerned with.