What this digital isolator brings to the board
The Texas Instruments ISO7331FCQDWRQ1 is a three-channel, unidirectional digital isolator built with capacitive coupling technology, rated for 3000 Vrms isolation and 25 Mbps data rate.
Three channels, two on one side — why the split matters
The channel configuration is 2 inputs on side 1 and 1 input on side 2, which suits designs where the majority of signals cross from the primary domain to the secondary, with a single return path. Propagation delay is 58 ns max in both directions, with pulse-width distortion held to 4 ns max — tight enough for SPI and UART links at moderate clock rates. Rise and fall times are 3 ns and 2 ns typical, keeping edge transitions clean without excessive ringing.
Automotive temperature range and CMTI
Common-mode transient immunity is a minimum 25 kV/µs, meaning fast switching from nearby motor drives or solenoid drivers won't glitch the data stream. No isolated power is provided on-chip — you supply separate isolated rails for each side.
Lifecycle and sourcing
For dual-sourcing or supply resilience, the ISO7221CDR is a two-channel unidirectional isolator with the same 25 Mbps data rate and 25 kV/µs CMTI, though it lacks the third channel and the AEC-Q100 automotive grade.