A capacitor cell is provided. A first PMOS transistor is coupled between a power supply and a first node, and has a gate connected to a second node. A first NMOS transistor is coupled between a ground and the second node, and has a gate connected to the first node. A second PMOS transistor is coupled between the second node and the first node, and has a gate connected to the second node. A second NMOS transistor has a drain connected to the first node, a gate connected to the first node, and a source connected to the ground or the second node. The first and second PMOS transistors and the first and second NMOS transistors are arranged in the same row. The second PMOS transistor is disposed between the first PMOS transistor and the first and second NMOS transistors.