A sense amplifier is provided. The sense amplifier comprises a first and second cross-coupled transistor pairs, a first and second current sources, a first digital input transistor, and a second digital input transistor. The first and second ends of the first cross-coupled transistor pair are coupled to an operating voltage, the first and second back gate ends of the first cross-coupled transistor pair are coupled to a first and second output ends respectively. The first and second back gate ends of the first cross-coupled transistor pair are coupled to a first and second output ends respectively, and the first and second ends of the first cross-coupled transistor pair are coupled to a first digital input end and second digital input end respectively.