What this isolator covers — and what it doesn't
The ADUM1400CRWZ-RL is a 4-channel, unidirectional digital isolator from ADI's iCoupler series, built on magnetic coupling technology. The 4/0 input-to-output channel count means all four channels run in the same direction — from Side 1 to Side 2 — so it handles a 4-bit wide bus or four independent signals, but not bidirectional lines like I2C without external direction control.
At 90 Mbps, this part keeps up with fast SPI clocks (up to 45 MHz half-duplex or 90 MHz in some modes) and high-speed UART links without adding a full bit-time of delay. The 32 ns max propagation delay and 2 ns max pulse-width distortion mean the output waveform stays close to the input shape, which matters when you're daisy-chaining multiple isolators or running a timing-critical sensor interface. If your bus runs slower than 10 Mbps, a lower-speed grade in the same family saves cost; if you need 150 Mbps, look at the ADUM140D or ADUM140E series.
The 2500 Vrms isolation rating is standard for basic functional isolation in industrial control, motor drives, and medical equipment where the working voltage stays under 300 Vrms continuous. It also carries a minimum common-mode transient immunity of 25 kV/µs, which keeps the data link intact during fast voltage surges like those from a motor-drive IGBT switching event. For reinforced isolation or higher working voltages (e.g., 600 Vrms mains), a part with 5000 Vrms or higher rating is needed.