SPI bus isolator with 7 channels — what the channel map buys you
The ADUM3151ARSZ is a 7-channel SPI digital isolator from Analog Devices' iCoupler SPIsolator family, built around magnetic coupling technology. It provides 3750Vrms isolation across a unidirectional channel configuration with 5 channels on Side 1 and 2 on Side 2 — a split that maps directly to a standard SPI bus: SCLK, MOSI, MISO, plus up to three chip-select or control signals on the primary side, and two return lines (typically interrupt or ready signals) on the secondary side. The 2Mbps data rate supports most industrial SPI peripherals up to 2 MHz clock, though it won't keep up with high-throughput ADCs or serial Flash running at 20+ MHz.
25 kV/µs CMTI and 25 ns propagation delay — margin for noisy environments
Common-mode transient immunity is rated at a minimum 25 kV/µs, which means this isolator holds its data integrity through fast voltage transients common in motor-drive inverters, solar inverters, and industrial power stages. Propagation delay is 25 ns max in both directions — tight enough for daisy-chained SPI buses where cumulative latency matters. Pulse-width distortion stays under 3 ns, so the duty cycle of the SPI clock is preserved across the barrier. Rise and fall times are a typical 2.5 ns, which keeps edge rates clean without excessive ringing on short PCB traces.
No isolated power is generated on-chip — you supply Vdd on both sides separately, which is typical for multi-channel SPI isolators.
20-SSOP package — rework and footprint notes
Housed in a 20-SSOP package (0.209 inch body width, 5.30 mm), surface-mount only. The 1.27 mm pitch is friendly for hand rework with hot air — no hidden pads, no exposed paddle.
For dual-source planning, the ADUM3150 is a pin-compatible sibling in the same SPIsolator family — the key difference is the channel-direction split; the ADUM3151ARSZ has a 5/2 unidirectional configuration versus the ADUM3150's 3/1 arrangement. Confirm the channel map against your SPI signal set before substituting.