ywguo
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Hi, Croaker,
Let's discuss it with an N-bit flash ADC. It needs 2^N comparators and references. Normally the references are generated using a resistor ladder, which is tied between the positive reference (ref+) and the negative reference (ref-). If the resitive ladder is composed of 2^N resistors of equal resistance, the most negative reference tied to one of the comparators is Vref-. The most positive reference tied to one of the comparators is (Vref+-Vref-)×(1-1/2^N)+Vref-. Then one LSB is equal to (Vref+-Vref-)×(1/2^N). However, if the resistive ladder is composed of (2^N-1) resistors of equal resistance, the most positive reference tied to one of the comparators is Vref+. The one LSB is equal to (Vref+-Vref-)÷(2^N-1). I think it depends on your choice.
Best regards, Yawei
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