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Comments on Why 3.3V instead of 3V?

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Why 3.3V instead of 3V?

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Usual values used in doing electronics/power supplies are almost always round numbers:

  • 5V
  • 12V
  • 28V
  • 48V
  • 60V

I understand that in some cases ICs are built to accept the voltage directly coming from the lithium-ion cell in order to simplify the power stage, therefore, having 4.2V input.

But, what is the reason behind having a 3.3V voltage level omnipresent instead of 3V?

power-supply voltage
posted almost 4 years ago
1y ago by Lorenzo Donati‭
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2kind‭
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Andy aka‭ wrote almost 4 years ago · edited almost 4 years ago
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24 volts is probably used more often than 28 volts and quite possibly 72 volts is more common than 60 volts. 15 volts is also commonly used.

2kind‭ wrote almost 4 years ago · edited almost 4 years ago
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I've been using 72V extensively and found that 60V was more common simply because it's in the "Low Voltage" category. It was battery-powered, though. Still, why 3.3V and not 3V? Most(every?) of the IC's accepting 3.3V could accept 3V so I assumed there is some historic reason behind the 3.3 value.

Nick Alexeev‭ wrote almost 4 years ago
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We could also add 1.8V and 2.5V to the question.

Olin Lathrop‭ wrote almost 4 years ago
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It's a number somebody picked from a whole set of tradeoffs. Note that 3.3 V is just about 2/3 of 5 V.

2kind‭ wrote over 3 years ago
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Everyone's right in one way. There is no way to close the question other than deleting it so I will leave it here unanswered.

leroy105‭ wrote over 3 years ago
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Actually I think this is a really good question. It's kind of more historical though I guess (and I don't know the answer either).