2.5 V reverse standoff, 145 pF — signal-line ESD clamp
The ESD5Z2.5T5G is a single-channel unidirectional Zener ESD protection diode from onsemi, designed to clamp transients on low-voltage signal lines. The 145 pF capacitance at 1 MHz is low enough for most general-purpose data interfaces up to a few MHz, though it will load higher-speed differential pairs.
120 W peak pulse — surge energy rating for 8/20 µs
Rated at 120 W peak pulse power for an 8/20 µs waveform, with a clamping voltage of 10.9 V at 11 A peak pulse current. This energy rating suits protection against ESD strikes or low-energy surge events on I/O lines, but it is not intended for power-line protection — the part explicitly lacks power line protection.
SOD-523 — footprint for compact PCB layout
Housed in the SOD-523 package, also known as SC-79. This surface-mount package suits dense PCB layouts where space is tight.