50 Mbps capacitive isolator for automotive signal chains
The Texas Instruments ISO6721BQDRQ1 is a two-channel, unidirectional digital isolator using capacitive coupling technology, rated for 3000 Vrms isolation and 50 Mbps data rate. It belongs to the Automotive, AEC-Q100, Functional Safety (FuSa) series, qualified for deployment in safety-rated automotive systems such as battery management, traction inverter gate-drive interfaces, and CAN/SPI isolation barriers. The part supports a dual-supply range of 1.71V to 1.89V on one side and 2.25V to 5.5V on the other, allowing direct interface between 1.8V, 3.3V, and 5V logic domains without external level translation.
100 kV/µs CMTI — what it means for motor-drive and inverter designs
Common-mode transient immunity of 100 kV/µs minimum is the key parameter for maintaining data integrity in high-side gate-drive or phase-voltage sensing applications where fast-switching SiC or IGBT stages produce dv/dt events exceeding 50 kV/µs. A part with lower CMTI would corrupt the output under those edges, causing spurious faults or desaturation detections. This rating, combined with 18 ns propagation delay and 2.6 ns rise/fall times, keeps the isolation link transparent to the control loop timing budget.
Package, supply, and temperature grade for BOM fit
The dual-supply architecture means each side of the isolation barrier can run at a different voltage — for example, a 3.3 V MCU domain on side 1 and a 5 V sensor interface on side 2 — without needing a separate level shifter IC.
For volume production, qualifying a second source within the same functional safety grade is advisable to avoid sole-source exposure on the isolation barrier.