Texas Instruments 74HCT165 8-Bit Parallel-in Serial-out Shift Register, DIP16,

The Texas Instruments 74HCT165 is a high-speed CMOS logic integrated circuit configured as an 8-bit parallel-in, serial-out shift register. It features complementary serial outputs (Q7 and Q7) from the last stage, providing greater design flexibility in digital data conversion applications.

When the active-low parallel load (PL) input is driven low, data from the D0 through D7 inputs is loaded into the register asynchronously, enabling rapid parallel data entry. With PL held high, data enters the register serially via the DS input and shifts one position to the right with each positive-going clock (CP) transition. This serial shifting capability allows for easy expansion by connecting the Q7 output to the DS input of a subsequent device, effectively creating longer shift registers for more complex parallel-to-serial conversion tasks.

For reliable and predictable operation, it is crucial that the low-to-high transition of the clock enable (CE) input only occurs while the clock (CP) is high. Additionally, both CP and CE should be held low before the low-to-high transition of PL to prevent unintended data shifting when the parallel load is disabled.

This device is engineered for high performance and efficiency. It offers significant power reduction compared to LSTTL logic families while maintaining direct LSTTL input logic compatibility. Key features include buffered inputs for improved signal integrity, balanced propagation delays and transition times for consistent timing, and high noise immunity for stable operation in electrically noisy environments. The outputs are robust, capable of driving 10 standard LSTTL loads or 15 bus driver LSTTL loads.

Encased in a standard 16-pin DIP (Dual In-line Package), this IC is designed for through-hole PCB mounting, making it suitable for prototyping, educational purposes, and legacy system maintenance. Its wide operating temperature range from -55°C to 125°C ensures reliability in