| 摘要 |
<p>An electrostatic discharge (ESD) protection circuit includes diodes connected in series back-to-back between the signal input and power supply terminals of the circuit to be protected. This allows the input signal to rise a selected distance above the supply voltage without triggering the ESD protection circuit. The ESD protection circuit can be fabricated in integrated form, with the diodes including a pair of P+ regions in an N-well or separate P+ regions forming PN junctions with separate N-wells. The diodes may also be formed in a layer of polysilicon over a field oxide region. Optionally, a second pair of back-to-back diodes can be connected between the signal input terminal and ground. This permits the input signal to fall a selected distance below ground without triggering the ESD protection circuit. <IMAGE></p> |
