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curvature on bandgap voltage reference (Read 3019 times)

coffeecat New Member Offline Posts: 7	curvature on bandgap voltage reference Oct 06^th, 2005, 6:41pm Has anyone seen a bandgap voltage characteristic which is concave upward :) ? All of what I have seen are concave downward . Any comments?
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ericjohnson Junior Member Offline Posts: 24	Re: curvature on bandgap voltage reference Reply #1 - Oct 7^th, 2005, 4:22pm I have a design which has "concave upward" V-T characteristics. And I did see several designs in the literature as well. Check out some bandgap papers published on JSSC in the early 80's.
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coffeecat

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Re: curvature on bandgap voltage reference
Reply #2 - Oct 7^th, 2005, 4:45pm

Thanks!

Also, how does one deal with the process variation (+/-15%) on Vbe which directly contributes to the tolerance of the bandgap voltage? The supply voltage is 1.2V.

And, how to minimize the contribution of input offset voltage (on the amplifier) to the bandgap voltage beside making the pnp's ratio larger (resistor ratio smaller) and careful layout?

Thanks!! Grin

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sheldon Community Fellow Offline Posts: 751	Re: curvature on bandgap voltage reference Reply #3 - Oct 9^th, 2005, 5:43am Coffeecat, You might also want to check the effect of the op-amp input bias current. Lateral pnp transistors have low beta and the input offset current can effect the bandgap core. Regards, Sheldon
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