Package and mounting
The ADUM4401CRWZ is a 4-channel, unidirectional digital isolator from Analog Devices' iCoupler series, using magnetic coupling to pass signals across a 5000Vrms isolation barrier. That 5000Vrms rating is the reinforced-isolation tier — the one you spec when the board has to survive a motor-drive short or a medical defibrillator pulse without letting the low-voltage side see the fault. The 25kV/µs common-mode transient immunity (CMTI) is the companion number: it tells you the part won't glitch or latch when a nearby IGBT switches at tens of kilovolts per microsecond. Three channels run from Side 1 to Side 2, one channel runs the other way — a 3/1 split that maps directly to a typical SPI bus (SCLK, MOSI, CS forward; MISO reverse) or a UART with flow control.
90Mbps data rate and the timing budget
Rated for 90Mbps, with a maximum propagation delay of 32ns in either direction and a pulse-width distortion cap of 2ns. The 32ns prop delay is the budget you need to account for in your SPI clock-to-data timing or your CAN bit-timing calculation — it's not zero, and at higher data rates it eats into setup/hold margin. The 2ns pulse-width distortion means the part preserves the duty cycle well, which matters if you're passing PWM or a clock signal across the barrier. Rise and fall times are 2.5ns typical, so the edges are clean enough that you won't need a Schmitt trigger on the output unless the trace runs a long way.
Operates from 3V to 5.5V on both sides — you can run the primary at 3.3V and the secondary at 5V, or any mix in between, without a separate level shifter. The 16-SOIC wide-body package (7.50mm body width) gives you the creepage distance to support the 5000Vrms rating — don't try to squeeze this into a narrow SOIC footprint; the pin spacing is part of the isolation design.