LATCH CIRCUIT

PURPOSE:To improve resistance against alpha-rays by reducing the reference potential of gates when noise is generated in a feedback signal by the alpha-rays, and forming the reference potential on the basis of the potential of several nodes in a latch circuit. CONSTITUTION:The output signals 615-618Q of respective gates constituting the latch circuit are inputted to the bases of TRs 609-612, the emitters of these TRs 609-612 are connected in common and its potential is dropped by a resistor 613. Said potential is applied to the bases of TRs 223, 233 as the reference potential VBB' of the 2nd and 3rd gates. The reference potential VBB of the 1st gate is fixed and the VBB is supplied to the base of a TR213. since the VBB' is held at the same potential as the VBB only by the Q, the VBB' is similarly changed by the potential change of the Q. Therefore, the reference potential VBB' of the 2nd and 3rd gates to which the fed back Q is inputted is set up to a level always lower than the Q, so that the latch is prevented from malfunction.