The KK74ACT651 is identical in pinout to the LS/ALS651, HC/HCT651. The KK74ACT651 may be used as a level converter for interfacing TTL or NMOS outputs to High Speed CMOS inputs. These devices consists of bus transceiver circuits, D-type flip-flop, and control circuitry arranged for multiplex transmission of data directly from the data bus or from the internal storage registers. Direction and Output Enable are provided to select the read-time or stored data function. Data on the A or B Data bus, or both, can be stored in the internal D flipflops by low-to-high transitions at the appropriate clock pins (A-to-B Clock or B-to-A Clock) regardless of the select or enable or enable control pins. When A-to-B Source and B-to-A Source are in the real-time transfer mode, it is also possible to store data without using the internal D-type flip-flops by simultaneously enabling Direction and Output Enable. In this configuration each output reinforces its input. Thus, when all other data sources to the two sets of bus lines are at high impedance, each set of bus lines will remain at its last state. The KK74ACT651 has inverted outputs. TTL/NMOS Compatible Input Levels Outputs Directly Interface to CMOS, NMOS, and TTL Operating Voltage Range: 4.5 to 5.5 V Low Input Current: 1.0 A; 0.1 A @ 25C Outputs Source/Sink 24 mA