Four-channel isolator for the 3.3V signal boundary
The ADUM1442ARSZ is a 4-channel, unidirectional digital isolator from ADI's iCoupler® family, built with magnetic coupling technology. Data rate is 2Mbps — enough for GPIO, SPI up to 2MHz, and UART handshake lines, but not for full-speed USB or gigabit Ethernet.
Channel count and direction — 2/2 split
Four channels with a 2/2 input-side split (two inputs on side 1, two on side 2) means this part handles bidirectional isolation in a single package — two signals crossing the barrier each way. That is handy for isolated SPI (MISO, MOSI, SCK, CS) where you need two lines each direction, or for breaking ground loops on a pair of digital I/O lines. The unidirectional channel type is standard for iCoupler; if you need bidirectional (I²C-style) isolation, look at the ADUM1250 family instead.
Timing and transient immunity
Propagation delay is 180ns max (both directions), and pulse-width distortion is 8ns max — tight enough for most 2Mbps signalling without skew headaches. The 25kV/µs common-mode transient immunity (CMTI) is the spec that matters in motor drives and inverters: fast voltage slewing on the high-voltage side can couple through parasitic capacitance and flip bits in a weaker isolator. 25kV/µs is a solid industrial-grade figure; you can run this across a 600V DC bus with a 50ns rise time and the data stays clean. Rise/fall times are 2ns typical, so signal integrity on the output side is crisp without excessive edge rates that cause EMI.
No isolated power — plan your rail
This part does not include an integrated isolated DC-DC converter (Isolated Power: No). You need a separate isolated supply for the secondary side — either a dedicated iso-brick like the ADuM5000 or a discrete flyback. The supply voltage range of 2.25V to 3.6V on each side is wide enough to run from a 3.3V rail with margin, or from a 2.5V rail if the logic family allows. If you need a one-chip solution with built-in power, step up to the ADuM5401 series.
Active lifecycle — no obsolescence worry
ADI lists the ADUM1442ARSZ as Active. No NRND flag, no last-time-buy notice. ROHS3 compliant. For a production BOM line, this means you can qualify it for new designs without scheduling a second-source qualification down the road. The iCoupler platform is mature and widely second-sourced in function (though not pin-for-pin) by TI's ISO72xx and Silicon Labs' Si86xx families — but if you need an exact ADI drop-in, this is it.