Onsemi MC14021BDR2G: 8-Stage Static Shift Register Datasheet and Application Overview

The Onsemi MC14021BDR2G is a monolithic 8-stage static shift register constructed using MOS P-channel and N-channel enhancement mode devices in a single monolithic structure. This device belongs to the 4000B series of CMOS logic, renowned for its low power consumption and wide operating voltage range. It is designed for a broad spectrum of serial-in/serial-out data handling applications, including time delay circuits, data storage, and serial-to-parallel conversion.

Key Datasheet Specifications and Features

The operational characteristics of the MC14021BDR2G make it highly versatile for both industrial and consumer applications. Its wide supply voltage range from 3.0 V to 18 V allows it to interface easily with a variety of other logic families and operate in systems with non-standard voltage levels. A significant advantage is its exceptionally low power consumption, which is a hallmark of CMOS technology, especially under static conditions.

The device features a single serial data input, a clock input (CP), and a single serial output. The internal structure consists of eight master-slave flip-flops, which are positive-edge triggered. This means that data is shifted from one stage to the next on the low-to-high transition of the clock pulse. The static design allows the device to operate at clock frequencies down to 0 Hz (DC), making it suitable for very slow-speed or manual clocking applications without any data loss.

Key electrical characteristics include:

High Noise Immunity: Typical noise margin is 1.5 V at VDD = 5.0 V and 3.0 V at VDD = 10.0 V.

Low Power TTL Compatibility: Can drive two low-power TTL loads or one standard TTL load over the entire temperature range.

Balanced Propagation Delays

Standardized Symmetrical Output Characteristics

Application Overview

The primary function of a shift register is to move data bits in a linear fashion. The MC14021BDR2G excels in several common circuit configurations:

1. Serial-to-Serial Data Delay: The most straightforward application. An 8-bit word introduced at the serial input will appear at the output after eight clock pulses, effectively creating a digital delay line. The length of the delay is controlled by the clock frequency.

2. Simple Data Storage: The device can temporarily store a serial data stream. This is useful in buffering data between two systems operating at different speeds.

3. Serial-to-Parallel Conversion: While the MC14021BDR2G has only a serial output, its internal stages (pins 1 through 6, and 11) can be tapped to provide a parallel output representation of the serial input data. This is fundamental in interfaces where data is transmitted serially but processed in parallel, such as in simple data input for microcontrollers.

4. Ring Counters and Pattern Generators: By connecting the output back to the input, the register can be configured as a ring counter. Preloading a single '1' and circulating it creates a timing sequence for controlling other parts of a system. With additional logic gates, it can generate more complex repeating patterns.

ICGOOODFIND Summary

ICGOOODFIND: The Onsemi MC14021BDR2G is a robust and versatile CMOS 8-stage static shift register. Its key strengths lie in its extremely wide operating voltage range (3V-18V), very low static power consumption, and high noise immunity. It serves as a fundamental building block for applications requiring data shifting, temporary storage, time delay generation, and simple serial-to-parallel conversion, making it a reliable choice for classic digital design.

Keywords:

1. Shift Register

2. CMOS

3. Low Power Consumption

4. Serial-to-Parallel

5. Static Operation