50 Mbps capacitive isolator for I²C and SPI buses
The Texas Instruments ISO1643DWR is a 4-channel digital isolator using capacitive coupling, supporting both I²C and SPI communication at data rates up to 50 Mbps. The part is configured with four inputs on side 1 and two on side 2, handling bidirectional (I²C) and unidirectional (SPI) channels in a single device. This makes it a fit for mixed-bus isolation in industrial fieldbus interfaces, motor drives, and isolated sensor links where the protocol isn't purely I²C or purely SPI.
5000 Vrms isolation with 50 kV/µs CMTI
The isolation rating of 5000 Vrms covers reinforced isolation requirements for industrial and medical equipment where the barrier must withstand high-voltage transients. The common-mode transient immunity of 50 kV/µs (minimum) is the spec that matters when this isolator sits between a noisy motor-drive power stage and a controller — fast switching edges on the high-voltage side must not couple through and corrupt the low-voltage bus. Propagation delay is 70 ns (tpLH) and 88 ns (tpHL) maximum, with pulse-width distortion capped at 45 ns, which leaves timing margin for 50 Mbps SPI without needing to slow the clock.
Hot-swappable and robust-EMC design
The device is described as hot-swappable with robust-EMC bidirectional operation. Hot-swappability means the isolator can be inserted into or removed from a live bus without latching up or disrupting the bus state — useful in modular I/O systems where cards are swapped under power. The robust-EMC characterization suggests the part has been designed to maintain data integrity in electrically noisy environments, which aligns with the 50 kV/µs CMTI figure.
Package and temperature grade
Housed in a 16-SOIC wide-body (0.295-inch width, 7.50 mm) package, surface-mount. The wide-body SOIC provides creepage distance for the 5000 Vrms isolation rating — important for PCB layout where clearance and creepage must meet IEC 60950 or 60601 spacing rules.