摘要 |
In an input protection circuit, one end of a resistive element of a protection circuit is connected to an intermediate impedance point of a terminating device, which is connected between a pair of external terminals of a low amplitude differential interface circuit. The other end of the resistive element is connected to an anode terminal of a diode element. A cathode terminal of the diode element is connected to a reference potential terminal. As a result, even when one of external terminals of a low-breakdown voltage circuit is erroneously in contact with a signal terminal (i.e., a bus terminal which is always pulled up via a high resistance resistor) of the socket to be pulled up to a high voltage, the elements forming the circuit are greatly protected from deterioration and damages at low costs, while maintaining the quality of transmission signals. |