Pins 8-13 are internally connected to the magnetic shield around the Hall core. The new schematic reveals that leaving these floating invites noise. The correct method (per the new diagram) is to connect these pins to chassis ground via a 1MΩ resistor + 10nF capacitor in parallel. This drains static charge without creating ground loops.
Based on the revised internal structure, LEM’s new application note (AN-LAH103P-Rev4) recommends:
The release of this new schematic suggests that while the physical LAH103P module is nearing end-of-life (EOL), LEM has provided the corrected documentation to help engineers migrate to newer transducers (like the LV or HAH series). However, due to the massive installed base of Japanese servo drives (Panasonic Minas A5, Yaskawa Sigma-II), this schematic will remain critical for repair technicians for at least the next decade. lah103p schematic new
If you are designing a new product, do not use the LAH103P—use the newer LEM HLSR series. But if you are maintaining legacy equipment, this new schematic is your golden ticket.
If you are repairing a TV from 2018-2022 and see the LAH103P, understand this: It is likely a programmed microcontroller or a custom power ASIC. Pins 8-13 are internally connected to the magnetic
Without the lah103p schematic new, engineers often made three critical mistakes:
If you cannot find the host manual, you might just need the pinout to trace the voltage. While rare, some user-generated databases exist on audiophile forums (like Audiokarma or Vintage Radio forums). This drains static charge without creating ground loops
Because the old schematic showed an open-collector output, technicians added pull-up resistors to 5V or 3.3V. The new schematic shows this is now unnecessary and harmful. The output is a true voltage output. Adding a pull-up will cause current sinking conflicts and non-linear readings.