PURPOSE: To obtain a circuit of a high degree of integration that is suited to a defect relieving circuit which receives a specific address signal and produces a negative or positive pulse, by incorporating a programmable element to an address comparator.
CONSTITUTION: The reference voltage of a current switching type logic circuit is applied to a terminal N1 and the voltage of a constant level is applied to a terminal N2 respectively. When a fuse F21 is cut, the current of a current source I11 flows to a resistance R11 via a transistor Q11 as long as the address signal has a high level of voltage at a node A1. Thus an emitter CO11 of an emitter follower Q31 has a low potential and the output PO is set at a low potential through a fuse F11. When the node A1 is set at a low level of voltage, the collector, the CO11 and the PO are set at low potentials. In the same way, the PO has a low potential when the node A1 is kept at a low level of voltage if the fuse F11 is cut. Therefore all outputs are negative when a specific address is supplied by cutting the fuses F11WF2m are cut in response to said specific address. Then the negative pulses are produced.
HONMA NORIYUKI
YAMAGUCHI KUNIHIKO
KANETANI KAZUO
NANBU HIROAKI
KAWAJIRI YOSHIKI
TANI KAZUHIKO
OHATA KENICHI
HITACHI DEVICE ENG