SN74HCS166QDRQ1

Shift Registers Overview

The SN74HCS166QDRQ1 is an automotive-grade, 8-bit parallel-load shift register from Texas Instruments. It features Schmitt-trigger inputs for noise rejection and operates within a supply voltage range of 2 V to 6 V. The device provides balanced CMOS push-pull outputs with ±7.8 mA drive capability at 6 V. It includes asynchronous clear (CLR), clock inhibit (CLK INH), and shift/load (SH/LD) control functions. Qualified under AEC-Q100 standards, it supports temperatures from -40°C to +125°C.

Shift Registers Feature Summary

• Schmitt-trigger inputs provide high noise immunity and tolerance for slow input signal transitions.
• Balanced CMOS push-pull outputs ensure similar sourcing and sinking current capabilities.
• Asynchronous clear function overrides all other inputs to reset flip-flops immediately.
• Clock inhibit input allows independent control over the clocking mechanism.

Shift Registers Applications

• Microcontroller input expansion
• 8-bit data storage

Shift Registers Procurement Notes

Verify the specific package variant against the datasheet, as the QDRQ1 suffix typically denotes SOIC-16. Confirm that the component meets the required AEC-Q100 grade specifications for your target temperature range. Ensure design compliance with absolute maximum ratings to prevent damage during operation or handling.

Shift Registers Selection Notes

Select this component when system requirements demand robust noise rejection in automotive environments. The Schmitt-trigger architecture is essential for applications involving noisy or slowly changing signals. Verify that the 2 V to 6 V operating range aligns with the available power rails in the target circuit design.

Shift Registers Part Context

This part belongs to the SN74HCS166-Q1 family of automotive shift registers. It shares functional similarities with standard logic devices but is optimized for harsh automotive conditions. The HCS series combines HCMOS speed with CMOS low power consumption and enhanced input characteristics.

Shift Registers FAQ

How does the SH/LD pin control data flow?

When SH/LD is high, the device enables serial shifting on clock pulses. When SH/LD is low, parallel data inputs are loaded synchronously on the next clock pulse.

What is the function of the CLK INH pin?

The CLK INH pin acts as a clock inhibit. Holding it high prevents clocking regardless of the CLK state, allowing the system clock to be free-running while stopping the register on command.