A memory device includes a memory array powered between a virtual supply and virtual ground nodes. A dummy memory array is powered between first and second nodes. A virtual supply generation circuit generates a virtual supply voltage at the virtual supply node as a function of a first control voltage. A virtual ground generation circuit generates a virtual ground at the virtual ground node as a function of a second control voltage. A first control voltage generation circuit coupled between the first node and a power supply voltage generates the first control voltage as tracking retention noise margin (RNM) of the memory array, the first control voltage falling as the RNM decreases. A second control voltage generation circuit coupled between the second node and ground generates the second control voltage as tracking RNM of the memory array, the second control voltage rising as the RNM decreases.