100 Mbps isolation — what it buys you
The ADUM1281CRZ is a two-channel, unidirectional digital isolator from Analog Devices' iCoupler family, built around magnetic coupling. Its headline rating is the 100 Mbps data rate — that is fast enough to isolate SPI clocks up to 50 MHz, CAN FD at full speed, or a pair of high-speed digital lines without adding timing jitter that messes up your bus budget. The 3000 Vrms isolation rating covers reinforced insulation for industrial motor drives, medical patient-interface circuits, and solar inverters where the safety barrier is non-negotiable. Common-mode transient immunity of 25 kV/µs means this part will not glitch when a nearby IGBT switches a few hundred volts in nanoseconds — a real concern in variable-frequency drives and UPS systems where the ground plane bounces hard. Propagation delay is 24 ns max each way, with pulse-width distortion held to 2 ns, so your timing margins stay predictable across temperature.
Supply and logic compatibility
Yes, it is compatible with 3.3 V logic: the inputs are CMOS thresholds that see a 3.3 V signal as a clean high. The unidirectional channel arrangement is one input on side 1 and one on side 2, which covers the common case of a TX/RX pair or a clock/data pair going opposite directions.
Package and field-fit
Comes in a standard 8-SOIC (3.90 mm width) — the same footprint as an SOIC-8 op-amp or a small logic gate. No isolated power on-chip, so you still need a separate DC-DC or an isolated module if the secondary side needs its own supply rail. Surface-mount only; rework with a hot-air station is straightforward, no underfill needed.
Lifecycle and sourcing
ROHS3 compliant, so it passes into European and California-restricted markets without exemption paperwork.