Fault tolerant 92160 bit multiphase CCD memory

technique in combination with laser burned fuses. During chip test, good and bad blocks are identified and the bad blocks are disconnected from the power supply by laser burned fuses. Each good block has its shorted address line fuse burned out which puts it in series with the othcr good blocks; Figure 2. No special masks are required. The good blocks are linked together by a serial addressing technique. In effect, thc linked blocks can be thought of as bit positions in a shift register such that if a “1” is inserted into the register, it can be shifted thru the register (blocks). Thus, to address a block, the “1” is shifted to the desired block and a common enable line is then activated. Data can then be written or read from the addressed block. Thus, at the system level, it is only necessary to guarantee a certain total number of good blocks to span the address range. No special method of block identification or bookkeeping of parts is required; this simplifies use.