74HC166D

Shift Registers Overview

The Toshiba 74HC166D is an 8-bit parallel-in/serial-out shift register fabricated using silicon gate C2MOS technology. It operates within a supply voltage range of 2.0 V to 6.0 V and supports a maximum clock frequency of 57 MHz at 5 V. The device features a gated clock input, an overriding direct clear input, and synchronous loading controlled by the SHIFT/LOAD pin. Propagation delays are balanced with typical values around 16 ns at 5 V. It is housed in a 16-pin SOIC package.

Shift Registers Feature Summary

• High-speed operation comparable to LSTTL while maintaining low CMOS power dissipation
• Synchronous parallel data loading enabled when the SHIFT/LOAD input is held low
• Direct clear input overrides all other inputs including the clock signal
• Integrated protection circuits against static discharge and transient excess voltage on all inputs

Shift Registers Applications

• Data acquisition systems requiring serial output from parallel sources
• Microcontroller peripheral expansion for I/O extension
• Digital communication interfaces utilizing serial data transmission
• General-purpose logic circuits requiring 8-bit storage and shifting

Shift Registers Procurement Notes

Verify the specific ordering suffix matches the required packaging format, as variations such as (BJ) indicate different tape-and-reel specifications. Confirm RoHS compliance status directly with the manufacturer or authorized distributors, as environmental declarations may vary by production batch. Ensure the component source is an authorized channel to guarantee authenticity and adherence to the specified operating ranges.

Shift Registers Selection Notes

Select this component when an 8-bit shift register with parallel load capability is required in a surface-mount design. The 74HC series compatibility ensures interoperability with standard logic families. Consider the 2.0 V to 6.0 V operating range for flexible power supply designs. Verify that the propagation delay characteristics meet the timing requirements of the target application circuit.

Shift Registers Part Context

This part belongs to the 74HC family of high-speed CMOS logic integrated circuits manufactured by Toshiba Semiconductor and Storage. The 74HC166D specifically implements an 8-bit shift register function. It is designed to replace older LSTTL equivalents while offering lower power consumption. The device is intended for general digital logic applications requiring reliable data shifting and storage.

Shift Registers Replacement Considerations

The Nexperia 74HC166D,653 is documented as a parameter-equivalent substitute. Designers should verify pinout compatibility and electrical characteristics against the original datasheet before implementation.

Shift Registers FAQ

How is the mode of operation determined?

The SHIFT/LOAD input controls the mode. When held high, the device performs serial shifting. When held low, parallel data inputs are enabled for synchronous loading on the next clock pulse.

What is the function of the CK-INH input?

The CK-INH (Clock Inhibit) input prevents clocking when shifted high. It should only be driven high while the CK input is held high to effectively inhibit the clock signal.

Does the clear input affect the clock signal?

Yes, the direct clear input overrides all other inputs, including the clock, and immediately sets all flip-flops to zero regardless of the clock state.