High Performance Silicon Gate CMOS. The MC74HC597A is identical in pinout to the LS597. The device inputs are compatible with standard CMOS outputs, with pullup resistors,they are compatible with LSTTL outputs. This device consists of an 8 bit input latch which feeds parallel data to an 8 bit shift register. Data can also be loaded serially. The HC597A is similar in function to the HC589A, which is a 3 state device.