TL5544 provides fully-floating DC supplies for energising two conventional 2-wire or 3-wire 4/20 mA or HART transmitters located in an (ATEX) hazardous area and repeating the current in other circuits to drive two safe-area loads. For smart transmitters, the unit allows bi-directional transmission of digital communication signals superimposed on the 4-20 mA loop current. Alternatively, the MTL5544 acts as a current sink for a safe-area connection rather than driving current into the load