3.3V rail ESD clamp in SOD-923
The onsemi ESD9X3.3ST5G is a single-channel Zener ESD protection diode designed for general-purpose circuit protection on 3.3V signal or power rails. Its 3.3V (max) reverse standoff voltage means it begins conducting only when the line exceeds that threshold, leaving the 3.3V rail undisturbed during normal operation. With a peak pulse power rating of 102W and a clamping voltage of 10.4V (max) at 9.8A peak pulse current (8/20µs waveform), this part clamps fast ESD transients to a level a 3.3V IC can survive — provided the IC's absolute-max rating is above 10.4V. The 80pF capacitance at 1MHz is moderate; it suits general-purpose I/O, I2C, SPI, and lower-speed interfaces.
Wide temperature range, small footprint
The SOD-923 package is one of the smallest ESD diode footprints available.
Active production, tape-and-reel delivery
The base product number is ESD9X3.3. No direct replacement is listed by onsemi — the ESD9X3.3 family is the active series. For a lower-capacitance alternative in the same package, evaluate the ESD9X3.3ST5G against the ESD9B3.3ST5G (if capacitance is the constraint).