Built-in self test system and method for two-dimensional memory redundancy allocation

摘要

A built-in self test system ( 124 ) and method for two-dimensional memory redundancy allocation. The built-in self test system is adapted to allocate two redundant columns ( 116 ) and one redundant row ( 120 ) to an embedded memory ( 104 ) as needed to repair single cell failures (SCFs) within the rows ( 108 ) and columns of the memory. The self-test system includes a left-priority encoder ( 136 ), a right-priority encoder ( 140 ), and a greater-than-two detector ( 144 ). The left-priority encoder encodes the location of the first SCF most proximate the most-significant bit of the corresponding word. The right-priority encoder encodes the location of the first SCF most proximate the least-significant bit of the corresponding word. The greater-than-two detector determines whether a word contains more than two SCFs. If the greater-than-two detector detects that a word contains more than two SCFs, the built-in self test system identifies the corresponding row as being a must-fix row, since the number of SCFs exceeds the number of redundant columns.