A circuit includes a first left transistor having a first left drain, a first left gate, and a first left source; a second left transistor having a second left drain, a second left gate, and a second left source; a third left transistor having a third left drain, a third left gate, and a third left source; a first right transistor having a first right drain, a first right gate, and a first right source; a second right transistor having a second right drain, a second right gate, and a second right source; a third right transistor having a third right drain, a third right gate, and a third right source; a left node electrically coupling the first left drain, the second left drain, the second left gate, the third right gate, and the third left drain; and a right node electrically coupling the first right drain, the second right drain, the second right gate, the third left gate, and the third right drain.