The Designer's Guide Community Forum

The Designer's Guide Community Forum
https://designers-guide.org/forum/YaBB.pl
Design >> Analog Design >> about breakdown voltage
https://designers-guide.org/forum/YaBB.pl?num=1257527182

Message started by rajesh14 on Nov 6^th, 2009, 9:06am

Title: about breakdown voltage
Post by rajesh14 on Nov 6^th, 2009, 9:06am

can anybody say how breakdown voltage of a particular device plays an important role in RF/ANALOG Applications..?

Title: Re: about breakdown voltage
Post by thechopper on Nov 6^th, 2009, 6:53pm

Hi rajaesh,

Your question sounds like too broad. From a general perspective I think it becomes an important parameter every time the device in question goes conneted to an input/output pin, where high voltages might hit the circuit....

Best
Tosei

Title: Re: about breakdown voltage
Post by Mayank on Nov 9^th, 2009, 11:10am

Hello rajesh,
The break-down voltage is a limiting voltage above which Source & Drain starts exhibiting very high conductance because of avalanche/Zener Breakdown Effect...In all applications including RF/Analog, we always operate much below the breakdown Voltage.....
Special care must be taken to ensure that voltage across any two MOS terminals should not go above the rated operation voltage(like 3.3V mos, 2.4V MOS, 1.2V MOS)....Esp in the case of a change in supply domain, like at the inputs as Tosei suggested, we place special ESD/CDM devices to ensure that the MOSFETs never come under stress....
i think that should suffice....

--Mayank

Title: Re: about breakdown voltage
Post by thechopper on Nov 9^th, 2009, 5:53pm

The temperature dependence of the BK voltage depends on whether it is Zener or avalanche. Zener BK depends on tunneling effect and its voltage decreases with temperature, while avalanche depends on impact ionization and thus the BK voltage increases with temperature.

Those temperature coefficients are sometimes used as reference voltages for some temp compensation circuits. That is another role that sometimes the breakdown voltage plays in analog design.

Best
Tosei

Title: Re: about breakdown voltage
Post by Mayank on Nov 9^th, 2009, 8:33pm

Hello Tosei,
You mean as the reverse Breakdown Voltage in Zener Diodes used in reference ckts sometimes ??

--Mayank

Title: Re: about breakdown voltage
Post by thechopper on Nov 10^th, 2009, 3:57am

Yes... Gray and Meyer classic text book shows some examples of those.

Best
Tosei