| 摘要 |
PURPOSE:To sufficiently clamp a surge pulse from outside an IC, unnecessitate an external protection diode, and contrive to largely reduce the cost by forming a low impedance diode between an emitter and a base. CONSTITUTION:An NPN type transistor 42 is formed on a P type substrate 40, and an emitter electrode 46 is connected to a GND electrode 48 via wiring body 50. An N type impurity layer 52 is diffused, which then forms the diode 54 by means of the junction with the substrate 40. A bias electrode 56 arranged to the anode side of the diode 54 is connected to the base electrode 58 of the transistor 42 by means of a wiring body 60. A bias electrode 64 joining with the substrate 40 by being inserted in an oxide film 44 is formed at the end of the wiring body 62. Since the distance between the electrodes 56 and 64 is set small, the impedance therebetween can be neglected, and accordingly the resistance value of the resistor parasitic to the diode can be reduced to a very small value. |
