NXP 74HC164BQ: An 8-Bit Serial-In, Parallel-Out Shift Register for Digital Logic Applications

In the realm of digital electronics, efficiently managing data conversion between serial and parallel formats is fundamental. The NXP 74HC164BQ is a quintessential component designed for this very purpose. As a high-speed Si-gate CMOS device, this 8-bit serial-in, parallel-out shift register offers a reliable and versatile solution for expanding I/O capabilities in microcontroller-based systems and other digital logic circuits.

The core functionality of the 74HC164BQ is to accept a single stream of serial data and convert it into an 8-bit parallel output. It features two serial data inputs (DSA and DSB) that are internally ANDed, allowing for easy gating of the data stream. On the rising edge of each clock pulse (CP), the logic level present at the data inputs is shifted into the first flip-flop. This data then propagates through the eight stages on subsequent clock pulses, making the complete byte available at the parallel output pins (Q0 to Q7). A master reset input (MR), active LOW, allows for the synchronous clearing of all flip-flops, forcing all outputs to LOW regardless of the input states, which is crucial for system initialization.

A key advantage of the 74HC164BQ is its low power consumption, a characteristic of the HC family, making it suitable for battery-operated portable devices. Furthermore, it offers high noise immunity and the ability to drive up to 10 LSTTL loads, ensuring robust performance in noisy environments. Its operation is specified over a wide voltage range from 2.0 to 6.0 V, providing significant flexibility in interfacing with various logic families.

Typical applications for this shift register are extensive. It is commonly used for I/O expansion for microcontrollers, enabling control of multiple outputs like LEDs, relays, or displays with just a few GPIO pins. It is also integral in building data conversion circuits, simple data storage buffers, and as a fundamental building block in more complex sequential logic systems.

The "BQ" suffix denotes a DHVQFN package, which is a very small, leadless, and surface-mounted package. This makes the 74HC164BQ ideal for space-constrained PCB designs commonly found in modern consumer electronics, while still offering good thermal and electrical performance.

ICGOODFIND: The NXP 74HC164BQ is a highly efficient and compact solution for serial-to-parallel data conversion. Its low power consumption, high noise immunity, and small package size make it an excellent choice for modern digital designs, from simple DIY projects to complex industrial systems requiring reliable data shifting and I/O expansion.

Keywords: Serial-In Parallel-Out, Shift Register, I/O Expansion, Low Power Consumption, CMOS Logic.