SPI-controlled isolated smart switch with integrated power
The SI83408BDA-IF: It integrates isolated power on the secondary side, eliminating the need for a separate isolated DC-DC converter in the BOM. All four channels are configured as inputs on side 1 (4/0), making this part a downstream switch controller rather than a bidirectional data isolator — it receives SPI commands from a host MCU and drives isolated outputs on the field side.
Isolation and transient immunity for motor-drive environments
Rated at 1500 Vrms isolation voltage, this device provides basic insulation for industrial equipment operating within the IEC 60950-1 reinforced isolation framework when used with proper PCB creepage distances. Common-mode transient immunity of 100 kV/µs minimum means the isolator maintains data integrity when a motor drive or inverter switches at high dV/dt — a 600 V bus switching in 100 ns generates a 6 kV/µs transient, well within this part's margin. Propagation delay is 3.5 µs (tpLH) and 4.5 µs (tpHL) maximum — adequate for relay actuation, valve control, or PLC digital outputs, but not for high-speed data links or encoder feedback.
Active production and compliance documentation
The part is ROHS3 compliant, meaning it contains no restricted substances above the exemption thresholds under EU Directive 2011/65/EU, and is suitable for global shipments without additional compliance paperwork.
Surface-mount assembly with a tray shipping format — no tape-and-reel, so pick-and-place feeders require tray handling or a tube-to-tape conversion for high-volume lines.
Sourcing and cross-reference note
The closest functional peer in the same family is the SI83404AAA-IF, which shares the same 4-channel unidirectional SPI architecture and 1500 Vrms isolation but has a slower rise/fall time (3 µs typ vs 2 µs typ) and different propagation delay characteristics.