The ADUM1285ARZ is a two-channel, unidirectional digital isolator from Analog Devices' iCoupler series, built around magnetic coupling technology. It provides 3000 Vrms isolation between a logic input side and an output side, with both channels oriented from side 1 to side 2 (2/0 input configuration).
1 Mbps data rate — what it buys you
With a maximum data rate of 1 Mbps, the ADUM1285ARZ is a mid-speed isolator. It comfortably handles UART at standard baud rates up to 921600, SPI clock up to 1 MHz, and most industrial fieldbus signals (RS-485, CAN at 1 Mbps). The 50 ns maximum propagation delay (tpLH/tpHL) and 10 ns pulse-width distortion mean timing skew is tight enough for synchronous interfaces at this speed. If your application needs faster isolation — say, 10 Mbps or 150 Mbps for high-speed SPI or parallel buses — you would step up to the ADUM1285BRZ or ADUM1285CRZ variants in the same package.
25 kV/µs CMTI — why it matters in noisy environments
Common-mode transient immunity is specified at a minimum of 25 kV/µs. This is the isolator's ability to reject fast voltage transients that appear simultaneously on both sides of the isolation barrier — exactly what happens when a motor drive switches an IGBT or a relay coil de-energizes. A CMTI below the transient slew rate can cause data corruption or output glitches. At 25 kV/µs minimum, the ADUM1285ARZ handles the switching noise found in most industrial and automotive power stages without extra filtering.