The 74LV595 is an 8 stage serial shift register with a storage register and 3-state outputs. Both the shift and storage register have separate clocks. It is a low-voltage Si-gate CMOS device and is pin and functionally compatible with the 74HC595 and 74HCT595.
Data is shifted on the positive-going transitions of the SHCP input. The data in the shift register is transferred to the storage register on a positive-going transition of the STCP input. If both clocks are connected together, the shift register will always be one clock pulse ahead of the storage register.
The shift register has a serial input (DS) and a serial output (Q7S) for cascading the device. It is also provided with an asynchronous reset input MR (active LOW) for all 8 shift register stages. The storage register has 8 parallel 3-state bus driver outputs. Data in the storage register appears at the output whenever the output enable input (OE) is LOW.