A circuit comprises a first path, a second path, a current generating circuit, and a sense amplifier. The first path has a first current having a first current value. The second path has a second current having a second current value. The current generating circuit is configured to generate a reference current having a reference current value based on the first current value and the second current value. The sense amplifier is configured to receive a third current having a third current value and to generate a logical value based on the reference current value and the third current value.