SOD-923 ESD clamp for 5V signal lines
The ESD9M5.0ST5G is a single-channel Zener ESD suppressor from onsemi, rated for 5V (max) reverse standoff with a typical breakdown at 5.8V and clamping to 9.8V at the peak pulse current of 1A (8/20µs waveform). Its 2.5pF capacitance at 1MHz keeps signal edges clean on high-speed interfaces like USB 2.0, HDMI, or automotive CAN bus — the low load won't degrade eye diagrams or add propagation delay.
Voltage thresholds and clamping margin
The 5V (max) standoff voltage sits below the 5.8V minimum breakdown, so a 5V rail at 5% tolerance (5.25V) stays below the avalanche region — no leakage creep during normal operation. Clamping at 9.8V at 1A peak pulse gives a 4.8V margin above the 5V rail — enough headroom for the downstream IC's absolute-max rating (typically 6-7V for 5V logic) without the suppressor conducting during a transient.
The SOD-923 package places the diode directly at the connector pin or IC input — short trace length minimises parasitic inductance that would otherwise reduce clamping effectiveness.