The PD7554A is a product of the PD7554, 7564 sub-series which is a 4-bit single-chip microcomputer with a small number of ports in a small package, which is enabled to operate even at the super-low voltage of 2.0 V so that it is optimized for handy-type systems operating with dry cells. The PD7554A is a low-order model in the PD7500 series (PD7554A only).