Capacitive-coupled dual isolator for industrial bus isolation
It provides galvanic isolation up to 2500 Vrms between input and output sides, with one channel per direction (1/1). Typical propagation delay is 475 ns max each way, with pulse-width distortion held to 14 ns max. The common-mode transient immunity (CMTI) is rated at a minimum of 25 kV/µs, making it suitable for noisy industrial environments such as motor drives, inverters, and PLC I/O modules. The 8-SOIC package and surface-mount footprint fit standard isolation layouts.
1 Mbps data rate and 475 ns delay — timing budget for control loops
At 1 Mbps, this isolator handles SPI-like clock rates up to 1 MHz and UART data at 115.2 kbaud with margin. The 475 ns max propagation delay per channel adds just under 1 µs round-trip for a read-write cycle. In a closed-loop motor control or ADC sampling path, that delay must be stacked into the loop phase margin. The 14 ns pulse-width distortion keeps duty-cycle errors small, so the isolator won't introduce significant skew on a PWM signal at moderate frequencies.
25 kV/µs CMTI — why it matters in a drive cabinet
Common-mode transient immunity of 25 kV/µs minimum means the output won't glitch when a fast voltage step (e.g., from an IGBT switching at 10–20 kV/µs) appears across the isolation barrier. In a motor-drive application where the ground potential between controller and power stage can shift abruptly, this CMTI rating is the difference between a clean data stream and corrupted bits. The capacitive coupling architecture inherently handles these edges well, but the 25 kV/µs floor is the spec to verify against your system's worst-case dV/dt.
For dual-sourcing or a pin-compatible second source, the ISO7221 family includes multiple speed and channel-count variants in the same 8-SOIC footprint — the base product number is ISO7221.