The marking M3966M is a verification code often found on small QFN/PDFN MOSFETs used in high-power density circuits, such as laptop motherboards and GPU VRAM power stages.
. You should see a voltage drop (typically 0.4V to 0.7V) in one direction (internal body diode) and an open circuit in the other. Gate-Source Isolation m3966m mosfet verified
Performance Testing: A verified genuine M3966M should have an on-resistance ( The marking M3966M is a verification code often