US Patent 7495979 Method and system for in-situ parametric SRAM diagnosis

This invention is about a system for diagnosing memory cells in a memory module. A first multiplexer module selectively connects a diagnosis signal in response to a multiplexer control signal to a data line associated with a predetermined memory cell. A second multiplexer module connects the data line to the predetermined memory cell via the bit line in response to a bit selection signals. Similarly, a complement diagnosis signal may be connected to a predetermined memory cell via the complement data line and bit line through the same control and bit select signals. A pair of access pads are provided for passing the diagnosis signal and the complement diagnosis signal for external accessing.