74LS165 Serial-Out Shift Register

Product Overview

The 74LS165 is a high-speed Low-Power Schottky 8-bit Parallel-In Serial-Out shift register integrated circuit. It provides a simple and reliable solution for expanding digital input pin capacity on microcontrollers such as Arduino, Raspberry Pi, and PIC systems by reading eight parallel data lines and outputting them serially over a minimal number of control lines.

Technical Performance

When the shift/load input is held low, parallel data from the eight inputs is loaded directly into the register asynchronously. When switched high, data is shifted out serially on every clock pulse. Featuring complementary serial outputs and an active-low clock enable input, the chip provides smooth cascaded operation to daisy-chain multiple ICs together for reading vast input arrays.

Common Applications

Widely used in embedded systems for reading switch matrix arrays, keypad inputs, DIP switches, and external digital sensor sets where microcontrollers run low on available GPIO pins.