Circuit Implementation, Operation, and Simulation of Multivalued Nonvolatile Static Random Access Memory Using a Resistivity Change Device

Figure 14

(a) Reference resistances. 𝑅_refa is fixed and 𝑅_refb is changed from 0 to 100. 𝑅_refa//𝑅_refb shows the parallel resistance of 𝑅_refa and 𝑅_refb. (b) The difference between reference resistances (the amount of margins separating the states). 01 shows the difference between 𝑅_refa and 𝑅_refb (𝑅_refa−𝑅_refb). 10 shows “𝑅_refb−𝑅_refa//𝑅_refb”. 11 shows the value of 𝑅_refa//𝑅_refb.

(a) Reference resistances

(b) Margins of reference resistances