Re: opamp design for bandgap
sina25 wrote
The OPAMP ensure that two nodes have the same voltage in a bandgap voltage reference; this nodes are conected to the OPAMP inputs
How does the OPAMP ensure that these two nodes have the same DC voltage? (=0.7 Volts).............. by its simetry?.
I understand that in AC the two inputs can have the same voltage, by its feedback and its high gain; but
why in DC?
Thanks
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If both the inputs to an opamp in a BGR is 0.7V then my ICMR(min) has to be less than 0.7V. I am designing the same with a 5V process and 0.756V VTh , is it possible for me to acheive that small ICMR(min) value. I am trying with a NMOS type input differential pair as the first stage of the opamp.
Thanx with advance ................