Described is an apparatus which comprises: a memory bit-cell; a local bit-line (LBL) coupled to the memory bit-cell via a read port device; a NAND gate circuitry coupled to the LBL; and a stack of keepers coupled to the LBL, wherein at least one transistor of the stack of keepers is controllable according to an output of the NAND gate circuitry, wherein the stack of keepers includes transistors with variable strength which are to be turned on overtime.