SN74ALS166D

Shift Registers Overview

The SN74ALS166D is a parallel-load 8-bit shift register from the ALS logic family, housed in a 16-pin SOIC package. It operates within a supply voltage range of 4.5 V to 5.5 V and supports an operating temperature range of 0°C to 70°C. The device features buffered inputs with clamping diodes and includes gated clock (CLK and CLK INH) inputs for flexible timing control. Electrical characteristics specify a maximum clock frequency of 45 MHz, propagation delays ranging from 2 ns to 14 ns depending on the signal path, and output drive capabilities of -0.4 mA high and 8 mA low.

Shift Registers Feature Summary

• Supports synchronous parallel loading and serial shifting operations controlled by dedicated mode selection inputs.
• Features dual clock inputs allowing one channel to function as a clock enable or inhibit gate.
• Includes a direct overriding clear input that forces all flip-flops to zero regardless of other active signals.

Shift Registers Applications

• Parallel-to-serial data conversion circuits
• Serial-in/parallel-out data buffering systems
• Digital sequence generation and pattern storage

Shift Registers Procurement Notes

Verify the specific ordering suffix against the manufacturer's current Package Option Addendum to confirm the exact physical package type and production status. Confirm RoHS compliance and lead finish specifications required for your assembly process. Ensure the selected variant matches the required thermal impedance and moisture sensitivity level for your manufacturing environment.

Shift Registers Selection Notes

Select this component when designing TTL-compatible systems requiring an 8-bit shift register with simultaneous parallel load capability. The ALS series offers improved speed over standard variants while maintaining compatibility with existing logic families. Verify that the system power supply remains strictly within the 4.5 V to 5.5 V range to ensure reliable operation and prevent damage to the internal circuitry.

Shift Registers Part Context

This part belongs to the Texas Instruments SN74ALS166 family of parallel-load 8-bit shift registers. The 'D' suffix specifically denotes the plastic small-outline package configuration. This family is designed for applications requiring efficient data serialization and deserialization within digital logic systems utilizing standard TTL voltage levels.

Shift Registers Replacement Considerations

SN74ALS166DR

Shift Registers FAQ

How does the clock inhibition function work?

Clocking is managed through two inputs, CLK and CLK INH. Holding either input high inhibits clocking, while holding either low enables the other input. This allows the system clock to remain free-running while the register can be stopped via command.

What is the behavior of the CLR input during operation?

The CLR input provides a direct overriding clear function. When active, it overrides all other inputs, including the clock signals, and sets all flip-flops to zero immediately.