What this IsoPower digital isolator does on your board
The ADUM6421ABRNZ5-RL is a 4-channel digital isolator from Analog Devices' IsoPower and iCoupler families that integrates an isolated DC/DC converter right into the package — no separate isolated supply module needed. It uses magnetic coupling to pass signals across a 5000 Vrms galvanic isolation barrier at up to 100 Mbps, with a unidirectional channel configuration: three channels on side 1, one on side 2. Typical environments are industrial motor drives, factory automation, medical equipment, and any system where you need to break ground loops or protect low-voltage logic from high-voltage transients.
5000 Vrms isolation and 75 kV/µs CMTI — where the margin lives
The 5000 Vrms isolation rating is the reinforced-grade barrier that lets this part sit between a mains-referenced power stage and a human-accessible control interface. The 75 kV/µs common-mode transient immunity (CMTI) is the spec that keeps data from corrupting when a SiC or IGBT switches at high dV/dt — a motor-drive inverter can easily couple several kV/µs across the barrier, and if the isolator's CMTI is too low you'll see bit errors on the SPI or UART lines. This part's 75 kV/µs minimum gives comfortable margin for most industrial drives and even some traction inverters.
100 Mbps data rate and 17 ns propagation delay — timing budget
At 100 Mbps the ADUM6421ABRNZ5-RL can carry a 50 MHz SPI clock or two 25 MHz parallel data lines without violating setup/hold on the receiving side. The max propagation delay is 17 ns in both directions, with a 5 ns pulse-width distortion — that matters for clock-synchronous interfaces where the data and clock paths must stay matched. The 2.5 ns rise/fall time is fast enough for clean edges at 100 Mbps but not so fast that it rings badly on a poorly terminated trace; still, keep the trace length under a few inches on the high-speed side.
Package and temperature grade — board-fit reality
The wide-body SOIC gives the creepage distance needed for the 5000 Vrms rating — don't substitute a narrow-body package from a different variant without checking the clearance.
Lifecycle and sourcing
It is ROHS3 compliant. If you're dual-sourcing, the standard ADUM6421ABRNZ5 (without the -RL suffix) is the same silicon but shipped in a different reel/tube quantity; verify the packaging code matches your assembly line's feeder requirements.