OPA4197: e-trim technology use in OPA4192

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Unlike older parts that where laser trimmed at the wafer-level, e-trim refers to package level trim - the parts are trimmed AFTER being packaged and thus do not exhibit parametric shift related to packaging stress - this result in higher precision vis-à-vis wafer trim especially when it comes to Vos and offset drift. 

OPA4192 and OPA4197 use the same die but the latter one is trimmed to a lower precision, which shortens required final test time, and for that reason it is less costly to manufacture.