BIPOLAR PROM CELL AND BIPOLAR PROM INTEGRATED CIRCUIT

摘要

PROBLEM TO BE SOLVED: To improve the efficiency of delivery inspection and realize cost reduction, by inspecting each zener diode element every one bit before delivery inspection process, in a bipolar PROM integrated circuit wherein zener diode zapping technique is applied. ;SOLUTION: In an NPN type transistor Q1 for selecting data writing, the collector is connected with a zener diode element D2, and the emitter is connected with a control terminal 13, which is grounded via a selection switch. Before delivery inspection process, the selection switch is opened, and data input terminals 5, 6 are controlled at the respective levels. From a transistor Q3, a current is supplied to the base of the NPN transistor Q1 through a resistor R3, and the base potential rises. As the result, a current flows in the forward direction of the zener diode element D2, through the PN junction between the base and the collector of the transistor Q1, and the output of the zener diode element D2 appears on a data output terminal 7 through a resistor R8.;COPYRIGHT: (C)1997,JPO