What is the variation of your op amp's branch bias current? If you change Vdd from 2.6V to 5V, how much is the bias current? You say N7 linearity: if the N7 bias current increases too much, you may need to increase the N7 size (same as the other nch transistor bias). If this does not work than the correct cascade can limit the bias current variation.
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发表于 2017-3-5 17:17:25
