The HEF4720B and HEF4720V are 256-bit, 1-bit per word random access memories with 3-state outputs. The memories are fully decoded and completely static. Recommended supply voltage range for HEF4720B is 3 to 15 V and for HEF4720V is 4,5 to 12,5 V; minimum stand-by voltage for both types is 3 V. The use of LOCMOS gives the added advantage of very low stand-by power. The circuits can be directly interfaced with standard bipolar devices (TTL) without using special interface circuits. The memory operates from a single power supply. The separate chip select input (CS) allows simple memory expansion when the outputs are wire-O Red. If CS is HIGH, the outputs are floating and no new information can be written into the memory. The signal at O has the same polarity as the data input D, while the signal at O is the complement of the signal at O. The write control W must be HIGH for writing into the memory.
