yvkrishna
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Thanks everyone for the replies and suggestions.
@RobG, Thanks, this is what I was looking for, yes mismatch/noise is better for case with larger current split resistor. as the addnl contributor from amp offset is prop. to voff/r_split .
@analog_wiz, I dont have any paper, saw it in some old design.
@mists May be its fair to compare these 2circuits in the fig here a) 2 pmos current sources for current split. b) 1 pmos current source(2x sized) and resistors for current split.
Assuming both are designed for same nominal DC conditions, and major mismatch sources are current mirror, opamp offset. (a) is better if pmos current mirrors mismatch is small and opamp offset dominates. (b) is better if mirrors dominate the total o/p referred offset.
because in case (b) thers an additional source of mismatch due to improper current split (with a difference of voff/r_split) even though the pmos mir mismatch is minimised by the loop.
regards, yvkrishna
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