JPS56110256A - Integrated circuit - Google Patents

Abstract

PURPOSE:To constitute a D/A converter with a SIT drain current adjusted by providing two SIT's and an injector transistor supplying a bias current with the gate of SIT as a collector, on a substrate and in addition, providing a constant current circuit. CONSTITUTION:The first SIT1 having a drain terminal 4 and the second SIT2 having an input terminal 12 are provided on the substrate of a semiconductor. The first and second injector transistors 10 having the gate of each SIT as a collector are provided on the substrate. A constant current is applied to the first SIT1 and a drain current of the second SIT2 is maintained almost at a constant level. For this purpose, a current source 3 and a constant current circuit based on an emitter follower transistor 7 are provided between a drain terminal of the first SIT1 and the first and second injector transistors. As a result, the bias of the injector can be controlled and also a drain current on plural SIT's can be controlled. Therefore, a D/A convertion circuit can be constituted with ease.