150Mbps isolation channel with 3750Vrms reinforced rating
The Skyworks SI8661EC-B-IS1R is a 6-channel digital isolator built on capacitive coupling technology, delivering 150Mbps per channel across a reinforced 3750Vrms isolation barrier. That data rate handles full-speed SPI, UART, and parallel GPIO isolation without bottlenecking the bus — the 13ns typical propagation delay and 2.5ns rise/fall times keep the signal edges clean for the downstream logic. The 5/1 channel configuration (five forward, one reverse) suits mixed-direction isolation needs — for example, isolating an SPI bus (SCLK, MOSI, MISO, CS, plus a status line) while keeping one channel for interrupt or fault feedback from the isolated side.
CMTI and propagation — what they mean for motor-drive and industrial isolation
Common-mode transient immunity of 35kV/µs (minimum) is the spec that matters when this isolator sits between a 3-phase inverter's gate-driver outputs and the controller. Fast voltage slewing on the motor phases couples common-mode current across the isolation barrier; if the CMTI is too low, the receiver side sees false edges. At 35kV/µs, the SI8661EC-B-IS1R handles the worst-case switching edges from SiC and GaN half-bridges without bit errors. Pulse-width distortion is capped at 4.5ns maximum — important when the isolator passes PWM signals for motor speed control or heater duty cycles. A 100kHz PWM with 50% duty has a 5µs on-time; 4.5ns of distortion shifts the duty cycle by less than 0.1%, so the load sees the commanded average voltage within the control loop's margin. The unidirectional channel architecture means the direction is fixed at design time — not configurable like an isolator with directional control pins.