An apparatus comprises at least one processor and at least one memory including instruction code configured to, with the at least one processor, cause the apparatus at least to perform a successive approximation analog-to-digital conversion of an analog input, representing a result of multiplication of first and second vectors, to a digital output by determining an upper bound on the result of multiplication of the first and second vectors, identifying, based at least in part on the determined upper bound, at least a portion of the successive approximation analog-to-digital conversion to be skipped, and skipping the identified portion of the successive approximation analog-to-digital conversion.