GB1268175A - Integrated circuit - Google Patents

Abstract

1,268,175. Semi-conductor devices. HITACHI Ltd. 21 Jan., 1970 [27 Jan., 1969], No. 3047/70. Heading HlK. An integrated circuit includes a plurality of basic electronic circuits, e.g. AND gates, OR gates, multivibrators, mutually interconnected in a normal operational relationship by signal transmitting paths, and at least one electronic switch having a control electrode, the switch being provided in one of the paths. The switch may be a MISFET 11 comprising source and drain regions (20, 21), Fig. lb (not shown), with source and drain electrodes 12, 13 connected to terminal pads C, C<SP>1</SP>, and a gate electrode 14, forming the control electrode, connected to a terminal pad 17 by a conducting region 15 of the substrate (10). The MISFET 11 is connected in the signal paths 16 between the basic circuits A, B, and such a switch may be provided in some or each of paths 16. The gate electrodes of the switches are connected together. In operation, the gate electrodes are energized, and the switches checked for continuity via terminal pads CC<SP>1</SP>, DD<SP>1</SP> &c. The gates are then de-energized isolating the basic circuits A, B &c., which are then checked for their correct individual operation. For normal working the switches are closed by energizing the gate electrodes, enabling the integrated circuit to function as a whole. The device is said to enable complex integrated circuits to be checked in basic circuit form enabling faulty circuits to be located although they may be mounted in series, parallel, multistage, or contain feedback loops.