Semiconductor integrated circuit device

Abstract

A semiconductor integrated circuit device comprises a first terminal (denoted by VCC) connected to a power supply in a normally mounted state, a second terminal (denoted by SB) connected to a signal line in the normally mounted state and to a power supply in a reversely mounted state, a third terminal (denoted by SGND) connected to the ground in the normally mounted state, fourth terminals (denoted by HU−, HW−) connected to the signal line in the normally mounted state and to the ground in the reversely mounted state, electrostatic protective diodes (denoted by D, D) having anodes connected to the third terminal and cathodes connected to the fourth terminals and serving as means for protecting the fourth terminal in the normally mounted state, a current control resistor (R) having one end connected to the second terminal and serving as means for preventing the second terminal from being broken in the reversely mounted state, a Zener diode (ZD) having an anode connected to the third terminal and a cathode connected to the other end of the current control resistor (R). With this, destruction of the semiconductor integrated circuit device when it is reversely mounted onto a board or into a slot is prevented without providing any redundant external terminal.