Two-channel digital isolator for automotive signal isolation
The ADUM121N1WBRZ is a two-channel, unidirectional digital isolator from Analog Devices, part of the Automotive series. It uses magnetic coupling to provide 3000Vrms isolation between input and output, with a data rate of 150Mbps and common-mode transient immunity of 75kV/µs. The wide supply range of 1.7V to 5.5V lets it bridge 1.8V, 2.5V, 3.3V, and 5V logic domains without external level shifters.
75kV/µs CMTI — why it matters for motor-drive and inverter designs
The 75kV/µs minimum common-mode transient immunity is the spec that keeps data intact when fast-switching SiC or IGBT edges slam the isolation barrier. In a traction inverter, the high-side gate driver reference jumps hundreds of volts in nanoseconds; a lower CMTI part would glitch or latch, corrupting the PWM pattern. This part's 75kV/µs rating clears that edge without retransmission or bit errors. Propagation delay is 13ns max, with pulse-width distortion held to 3ns. Rise and fall times are 2.5ns typical. These numbers keep the timing budget tight enough for 150Mbps SPI or 5Mbps CAN FD without skew eating into setup-and-hold margins.