A reservoir capacitor includes a first capacitor group having two or more capacitors, which are serially coupled to each other between a first power voltage supply terminal and a second power voltage supply terminal, a second capacitor group having two or more capacitors, which are serially coupled to each other between a third power voltage supply terminal and a fourth power voltage supply terminal and a connection line suitable for electrically coupling a first coupling node between the capacitors of the first capacitor group to a second coupling node between the capacitors of the second capacitor group.