The 74HC/HCT173 are high-speed Si-gate CMOS devices and are pin compatible with low power Schottky TTL (LSTTL). They are specified in compliance with JEDEC standard no. 7A. The 74HC/HCT173 are 4-bit parallel load registers with clock enable control, 3-state buffered outputs (Q0 to Q3) and master reset (MR). When the two data enable inputs (E1 and E2) are LOW, the data on the Dn inputs is loaded into the register