16-SOIC wide-body isolation for motor-drive and industrial bus interfaces
The Skyworks SI8422AD-D-IS is a 2-channel, unidirectional digital isolator in a 16-SOIC wide-body package (0.295", 7.50 mm width). Capacitive coupling delivers 5000 Vrms galvanic isolation — enough to meet reinforced insulation requirements per IEC 60747-5-5 for motor-drive and inverter applications where the DC bus sits above 400 V. The 20 kV/µs common-mode transient immunity (CMTI) means it holds isolation integrity through the fast voltage transitions on the switching node of a half-bridge driver — a 600 V SiC or IGBT stage switching at 50 kHz generates edges that exceed 10 kV/µs easily.
1 Mbps data rate and 35 ns propagation delay — timing closure for isolated SPI and UART links
The 1 Mbps data rate covers isolated SPI, UART, and general-purpose logic-level signals. Propagation delay is 35 ns max (tpLH / tpHL) with a pulse-width distortion of 25 ns max — the asymmetry between rising and falling edges stays within a quarter of the bit period at 1 Mbps, so the receiver's sampling window does not close. Rise and fall times are 2 ns typical. The fast edges reduce the dead-time between data transitions but increase the coupling current through the isolation barrier — the 20 kV/µs CMTI spec ensures the output does not glitch when a common-mode transient coincides with a data edge.
The part does not include an isolated DC-DC converter — the secondary-side supply must come from an external isolated power module or a separate rail. Place a 0.1 µF ceramic capacitor within 2 mm of each supply pin (VDD1 and VDD2). The wide-body SOIC-16 footprint has a 1.27 mm pitch — the inner pins (pins 4-13) are the isolation barrier gap; no copper or trace should cross under the package body between the primary and secondary ground planes.
Active production — sourcing and lifecycle posture
The tube packaging (50 pieces per tube) suits prototype and low-to-mid volume assembly.