Isolation barrier and signal integrity for harsh environments
The ADUM3401TRWZ-EP is a 4-channel, unidirectional digital isolator from the iCoupler family, built around magnetic coupling technology. It delivers 2500Vrms isolation between the input and output sides, which is the standard rating for basic insulation in 24V industrial buses and general-purpose signal isolation. This makes it suitable for deployment in engine compartments, downhole instrumentation, or outdoor enclosures where the ambient temperature exceeds the commercial-industrial band.
Supply voltage flexibility and channel configuration
Each side of the isolator operates from a supply range of 3.135V to 5.5V, and the two sides can run at different voltages independently. This means a 3.3V microcontroller on side 1 can communicate with a 5V peripheral on side 2 without an external level translator — the isolator handles the voltage domain crossing natively. The channel layout is 3 inputs on side 1 and 1 input on side 2, all unidirectional. This 3/1 split is typical for isolating a SPI bus (SCLK, MOSI, CS) from the controller to the peripheral, with a single MISO line returning data. The fourth channel on the return side handles the feedback signal. Propagation delay is 50ns max in both directions, with a pulse-width distortion of 3ns max. The rise and fall times are 2.5ns typical — fast enough for the 10Mbps data rate without excessive edge ringing, provided the PCB trace length is kept under a few inches to avoid transmission-line effects.
Package and board-level integration
Housed in a 16-lead SOIC wide-body package (7.50mm body width), the ADUM3401TRWZ-EP uses the standard 1.27mm pitch that routes cleanly on a two-layer board. The wide-body SOIC provides 8.5mm creepage distance between the input and output pins, which meets the 2500Vrms isolation requirement without needing a slot in the PCB. No isolated power is integrated — the part is a signal-only isolator. Each side requires its own local supply rail and decoupling capacitors placed close to the VDD and GND pins. The 16-SOIC package is supplied in tube format, which is the standard shipping option for prototype and low-volume builds.
For BOM risk mitigation, the closest functional peer is the ADUM2401BRIZ, which offers 5000Vrms isolation in a 16-SOIC package with the same 10Mbps data rate and 3/1 channel configuration. If the higher isolation voltage is acceptable and the temperature range fits, the ADUM2401BRIZ is a direct drop-in replacement for the signal path.