Active production — 2500 Vrms capacitive isolator in wide SOIC
The Texas Instruments ISO7231CDWR is a general-purpose digital isolator using capacitive coupling to transfer signals across a 2500 Vrms isolation barrier. It packs three unidirectional channels in a 2/1 input-side/side-2 configuration, each rated for 25 Mbps data rate with 42 ns max propagation delay and 2.5 ns pulse-width distortion. The wide-body 16-SOIC package (7.50 mm body width) provides the creepage distance needed for reinforced isolation in industrial and motor-drive applications.
25 kV/µs CMTI — why it matters for motor drives and inverters
Common-mode transient immunity is rated at a minimum 25 kV/µs. In a variable-frequency drive or servo amplifier, the fast voltage slew on the motor phases couples through parasitic capacitance into the isolation barrier. If the isolator's CMTI is too low, the output glitches or latches, corrupting the gate-drive or encoder feedback. The 25 kV/µs floor here handles most industrial inverter rails up to 600 V bus without extra filtering.
The supply range spans 3.15 V to 5.5 V, so the same part works on a 3.3 V MCU side and a 5 V field-side interface without a separate level shifter. No derating needed for the isolation rating across this range.
Capacitive coupling vs optocouplers — no LED aging, consistent timing
Capacitive coupling uses on-chip SiO₂ capacitors rather than an LED and photodetector. The key advantage: no current-transfer-ratio (CTR) degradation over temperature or lifetime, so propagation delay and pulse-width distortion stay stable from first power-up to end of life. The 2 ns typical rise/fall time and 2.5 ns max pulse-width distortion make this part suitable for isolating SPI or UART links at 25 Mbps without bit-error concerns.
Package and footprint — wide-body 16-SOIC for creepage
Surface-mount assembly with standard reflow profiles; the wide-body footprint is shared across the ISO72xx family, so a layout designed for the ISO7231M or ISO7231 will accept this part without changes.