RT9742SNGV

RT9742SNGV is a USB high-side power switch from Richtek in a 3-pin SOT-23 package, with a fixed 0.5 A current limit for a single USB port or peripheral rail. It operates from 2.7 V to 6 V with a typical 70 mΩ on-resistance N-MOSFET and integrates over-current, short-circuit, under-voltage and thermal protection with reverse-current blocking, which protects the upstream 5 V rail from faulty downstream devices without a fuse or discrete load switch design. The S variant is the always-on 3-pin version with soft-start for hot-plug inrush control. Selection advice: the letters are the specification - SNGV is the 0.5 A SOT-23-3 code (marking 6V=), while the LNGV code is the 1 A grade and the GJ5 codes move to TSOT-23-5 with enable and flag pins, so confirm the full code rather than the RT9742 base name. The series carries UL E219878 and Nemko NO109777 approvals. Parameters verified against the Richtek RT9742 datasheet DS9742-10 ordering table.