NCID9401 & NCID9411 Quad-Channel Digital Isolators onsemi NCID9401 and NCID9411 High-Speed Quad-Channel Digital Isolators support isolated communications and allow digital signals to communicate between systems without conducting ground loops or hazardous voltages. The NCID9401 and NCID9411 High-Speed Quad-Channel Digital Isolators utilize onsemi's patented galvanic off-chip capacitor isolation technology and optimized IC design to achieve high insulation and high noise immunity. These are characterized by high common-mode rejection and power supply rejection specifications.