Which statement is false about ESD protection diodes?

Which statement is false about ESD protection diodes?

• A. They short out the power supply during ESD events
• B. They permanently short the circuit after ESD
• C. They clamp voltage to safe levels
• D. They provide a discharge path to ground

Answer: (B)

ESD protection diodes are used to keep transient voltages from harming sensitive electronics by giving the surge a fast, low-impedance path to ground or to the supply rails. They are connected from the signal node to ground and to Vcc, so when a sudden charge appears, a diode conducts and clamps the node voltage to a safe level, shunting most of the current away from the sensitive circuitry. This clamping happens only for the brief moment of the ESD pulse, so once the transient passes, the diode stops conducting and the circuit returns to normal; there is no lasting short. The statement claiming they permanently short the circuit after ESD is not how protection diodes are intended to work. In reality, they provide a discharge path to ground and keep the node voltage within safe limits during the event.

ESD protection diodes are used to keep transient voltages from harming sensitive electronics by giving the surge a fast, low-impedance path to ground or to the supply rails. They are connected from the signal node to ground and to Vcc, so when a sudden charge appears, a diode conducts and clamps the node voltage to a safe level, shunting most of the current away from the sensitive circuitry. This clamping happens only for the brief moment of the ESD pulse, so once the transient passes, the diode stops conducting and the circuit returns to normal; there is no lasting short. The statement claiming they permanently short the circuit after ESD is not how protection diodes are intended to work. In reality, they provide a discharge path to ground and keep the node voltage within safe limits during the event.