Introduction
Overall measurement accuracy in current-sense amplifiers is a function of both gain error and amplifier input offset voltage performance. Of the two error sources, amplifier input offset voltage can impact the design more so than gain error. If the sense resistor needs to be small to maximize power to the load and to minimize power dissipation; then amplifier input offset voltage becomes the dominant error term. To minimize load current sense error, a current-sense amplifier with a lower input offset voltage is required. By comparing the TS1100 against the MAX9634 side-by-side, the TS1100’s 3-to-1 improvement in amplifier input offset voltage translates into a 2x improvement in current measurement accuracy.