| 摘要 |
An I/O pad voltage protection circuit and method tracks a bias voltage of cascaded stages in order to avoid overvoltage stress in I/O transistors. An overshoot protection circuit controls overshoot current sinking to provide a clamp voltage equal to an I/O pad supply voltage, or other suitable reference voltage, during overshoot conditions, as a function of a reference voltage generated by a reference voltage generating circuit. An undershoot protection circuit includes a reference voltage generating circuit and controls undershoot current sinking to provide a clamp voltage approximately equal to an I/O pad ground voltage, or other suitable reference voltage, during undershoot conditions as a function of a reference voltage generated by the second reference voltage generating circuit.
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