Abstract
A device includes a first transistor having a first source terminal, a first drain terminal, and a first gate terminal; and a second transistor having a second source terminal, a second drain terminal, and a second gate terminal. The second source terminal is coupled to the first gate terminal and the first source terminal is coupled to the second gate terminal. The first transistor has a first threshold voltage, and the second transistor has a second threshold voltage different from the first threshold voltage.