74HC595 Shift Register

The 74HC595 is an 8-bit serial-in, parallel-out shift register with an 8-bit storage register. The device features a serial data input (DS), eight parallel data outputs (Q0-Q7), and a serial output for cascading (Q7′). It is commonly used to expand the number of I/O pins available on a microcontroller, enabling control of multiple outputs with a few pins.

Key Features:

• 8-bit serial-in, parallel-out shift register
• 8-bit storage register with tri-state outputs
• Serial input (DS) and serial output for cascading (Q7′)
• Three-state outputs (Q0-Q7)
• Low power consumption
• High-speed operation
• Cascadable with multiple 74HC595 ICs

Technical Specifications:

• Operating Voltage: 2V to 6V
• Maximum Clock Frequency: 100 MHz (at Vcc = 4.5V to 5.5V)
• Current Consumption: 80 μA (maximum, at Vcc = 6V)
• Output Current per Pin: 35 mA (maximum)
• Total Current through Vcc/GND: 70 mA (maximum)
• Propagation Delay Time: 23 ns (at Vcc = 5V)
• Package Types: 16-pin PDIP, SOIC, TSSOP
• Operating Temperature Range: -40°C to +125°C

Applications:

• LED displays
• Keypad interfaces
• Data acquisition systems
• Digital signal processing
• Memory addressing
• Control systems

Usage:

1. Connection:
   • Connect the Vcc pin to a 5V power supply (or appropriate voltage within the operating range).
   • Connect the GND pin to ground.
   • Connect the serial data input (DS) to the microcontroller’s data output pin.
   • Connect the clock input (SH_CP) and latch input (ST_CP) to the microcontroller’s clock and latch control pins.
   • Connect the parallel outputs (Q0-Q7) to the desired peripheral devices.
   • Use the serial output (Q7′) to cascade additional 74HC595 shift registers if needed.
2. Operation:
   • Send serial data to the DS pin while providing clock pulses to SH_CP.
   • Latch the data to the output pins by providing a pulse to the ST_CP pin.
   • Control multiple 74HC595 ICs in series by connecting the Q7′ of one to the DS of the next.
3. Programming:
   • Write code on the microcontroller to control the shift register.
   • Shift in data bits and latch them to update the outputs as needed.

Caution:

• Ensure the supply voltage does not exceed the maximum rated voltage to avoid damage to the IC.
• Handle the IC carefully to prevent damage from electrostatic discharge (ESD).
• Avoid exceeding the maximum current ratings to prevent overheating and damage.

Datasheet:
For detailed technical specifications, refer to the 74HC595 Datasheet.