What the 5000Vrms and 85kV/µs CMTI mean for your design
The Texas Instruments ISO7731DW is a 3-channel, unidirectional digital isolator built with capacitive coupling technology. Its headline rating is 5000Vrms of isolation voltage, which qualifies it for reinforced insulation in mains-connected industrial equipment, motor drives, and medical systems where safety isolation is required. The 85kV/µs common-mode transient immunity is the spec that matters in noisy environments like inverter stages or relay-heavy panels — it keeps the data path clean when ground potentials jump. With a 100Mbps data rate, it handles SPI, UART, and isolated CAN buses without timing pressure. The supply range spans 2.25V to 5.5V, so it bridges 3.3V and 5V logic domains on the same chip — no secondary regulator needed for level translation.