In an integrated circuit (IC) may have several functional blocks adapted to be inactivated independently from each other. At least one firewall cell may be embedded independently of other firewall cells in the vicinity of one functional block. The firewall cell may be electrically isolated from the functional block and may be powered by a constantly supplied voltage source in the IC. Firewall cells may be embedded in free locations on the IC in the functional block domain according to a design that may be free of constraints such as firewall cells array of firewall cells mini-island.