The SN74HC595N is a simple 8-bit shift register IC. Simply put, this shift register is a device that allows additional inputs or outputs to be added to a microcontroller by converting data between parallel and serial formats. Your chosen microprocessor is able to communicate with the The SN74HC595N using serial information then gathers or outputs information in a parallel（multi-pin）format. Essentially it takes 8 bits from the serial input and then outputs them to 8 pins.
This small DIP packaged IC contains an 8-bit, serial-in parallel-out shift register that feeds an 8-bit D-type storage register with parallel 3-state outputs.
Note：
This is a drop-in replacement for the 74HC595 shift register IC and should function just fine in any application the previous version could.
Get started with the Shift Register Guide
Features
8-Bit Serial-In, Parallel-Out Shift
Wide Operating Voltage Range of 2 V to 6 V
High-Current 3-State Outputs Can Drive Up to 15 LSTTL Loads
