Four-channel iCoupler for isolated SPI and general-purpose signal isolation
The ADUM7442CRQZ is a four-channel digital isolator from Analog Devices' iCoupler series, using magnetic coupling to pass signals across a 1000 Vrms isolation barrier. It is a general-purpose part — no integrated DC-DC converter, no reinforced safety rating — aimed at basic galvanic isolation in industrial interfaces, sensor readout chains, and control links where you need to break ground loops without the drift and aging of optocouplers. The channel configuration is 2 inputs on side 1 and 2 inputs on side 2, all unidirectional. That maps cleanly to a four-wire SPI bus (SCLK, MOSI, MISO, chip-select) with one device, or two isolated digital lines in each direction for a UART with flow control. The 25 Mbps data rate covers most SPI clock domains up to 25 MHz and all common asynchronous serial rates well beyond 115.2 kbps.
25 Mbps and 50 ns propagation delay — what they mean for bus timing
At 25 Mbps the maximum propagation delay is 50 ns in either direction, with pulse-width distortion held to 5 ns max. Common-mode transient immunity is rated at 15 kV/µs minimum. That is the figure that matters when this isolator sits between a controller and a motor-drive interface or a switching power stage — fast dV/dt events on the bus side must not glitch the data. 15 kV/µs is a solid industrial-grade number; for SiC or GaN inverter edges above 50 kV/µs you would step up to a higher-CMTI variant.
No isolated power is generated on-chip — each side needs its own local supply rail. That suits outdoor telecom cabinets, factory-floor PLC I/O modules, and HVAC controllers.