In summary, as power electronics systems get smaller LEM is introducing new families of compact open-loop current transducers which measure higher currents than earlier devices of the same size, or similar currents with smaller size. Excellent performance is obtained using a single custom ASIC to perform all signal processing and analog correction functions. The HOYS and HOYL sensors which are respectively ‘small’ and ‘large’ devices are for mounting on busbars up to 21 x 12 mm and 39 x 12 mm respectively. Together they cover the current range from 100 to 800 A_RMS with a maximum measurable current of 2000 A peak. These transducers have a fifth output pin, OCD, which indicates that an overcurrent condition has been detected on the primary current. Their compact size is due to the optimization of the magnetic circuit and package around the busbar and because there are no discrete electronic components inside the sensors except the Hall effect ASIC and two decoupling capacitors.