5700Vrms isolation in a 16-SOIC — what that buys you
The Texas Instruments ISO7821FDWR is a two-channel, unidirectional digital isolator using capacitive coupling to deliver 5700Vrms of galvanic isolation in a 16-SOIC package. It supports a data rate up to 100Mbps, with propagation delays of 16ns max and pulse-width distortion held to 4.6ns. The supply range spans 2.25V to 5.5V, so it can bridge 3.3V and 5V logic domains without a separate level shifter.
Common-mode transient immunity — the spec that keeps data clean in noisy environments
With a minimum common-mode transient immunity (CMTI) of 100kV/µs, the ISO7821FDWR can reject fast voltage transients that couple across the isolation barrier. In a motor-drive or solar-inverter design, where switching edges on the high-voltage side can slam the isolation barrier with several thousand volts per microsecond, this rating means the output stays in the correct logic state rather than glitching. The 2.4ns typical rise/fall time also keeps the signal edges sharp enough for 100Mbps throughput without excessive ringing.
The wide supply range and temperature grade also mean it fits across multiple BOM variants without requalification.