An accurate and robust +/-nV(T) extractor is introduced. Basically, th
e circuit consists of a current comparator and a source follower. The
output of the comparator controls the bias current level in the follow
er, and thus its low output resistance is divided by the loop gain pro
viding high accuracy in most applications. Experimental results using
commercial matched MOS transistor array TC4007, which have been compar
ed with the value obtained by classical methods, confirm the validity
of the proposed circuit.