SN74HC166DR

Shift Registers Overview

The SN74HC166DR is an 8-bit parallel-load shift register from the Texas Instruments HC logic family, housed in a 16-pin SOIC package. It operates on a supply voltage range of 2V to 6V and supports a recommended operating temperature range of -55°C to 125°C. The device features synchronous loading, serial-to-serial shifting, and an asynchronous clear function. Electrical characteristics include a maximum propagation delay of 45ns at 4.5V and output drive capabilities suitable for up to 10 LSTTL loads.

Shift Registers Feature Summary

• Synchronous parallel data loading capability controlled by the SH/LD input
• Asynchronous direct overriding clear (CLR) input that resets all flip-flops
• Gated clock inputs allowing CLK or CLK INH to enable shifting operations

Shift Registers Applications

• Increasing the number of inputs available to a microcontroller
• Parallel-to-serial data conversion circuits
• General-purpose digital logic expansion using simple GPIO pins

Shift Registers Procurement Notes

Verify the specific ordering suffix against the manufacturer's current Product Selection Guide to confirm package type, lead finish, and moisture sensitivity level. Ensure the procurement channel provides valid traceability documentation. Confirm that the component meets the required RoHS compliance status and environmental specifications for the intended deployment environment before finalizing acquisition.

Shift Registers Selection Notes

Select this component when an 8-bit shift register with synchronous parallel load and asynchronous clear is required. The HC series offers standard CMOS inputs compatible with TTL logic levels. Verify that the operating temperature range and supply voltage requirements align with the system design constraints. Consider the SOIC package dimensions for PCB layout compatibility.

Shift Registers Part Context

This part belongs to the SNx4HC166 family of 8-bit parallel-load shift registers manufactured by Texas Instruments. The family includes variants with different packaging options such as SSOP, PDIP, and TSSOP. All variants share the same logical functionality but differ in physical dimensions and thermal characteristics. The DR suffix specifically denotes the SOIC surface-mount package configuration.

Shift Registers Replacement Considerations

SN74HC166PW

Shift Registers FAQ

How does the SH/LD input control the device operation?

When SH/LD is high, the device shifts serial data on the rising edge of the clock. When SH/LD is low, parallel data inputs are loaded synchronously with the next clock pulse.

What is the function of the CLR input?

The CLR input provides an asynchronous clear function that overrides all other inputs, including the clock, and resets all internal flip-flops to zero.