AD421BN

series introduction

# AD421BN Product Series Introduction

## 1. Overview
The AD421BN product series represents a cutting - edge solution in the field of industrial instrumentation and control. Developed by Analog Devices, a leader in high - performance analog, mixed - signal, and digital signal processing (DSP) integrated circuits, the AD421BN series is designed to meet the demanding requirements of modern industrial applications. These devices are specifically engineered to convert digital signals into precise 4 - 20 mA current outputs, which are widely used in industrial control systems for transmitting process variables such as temperature, pressure, and flow.

## 2. Key Features

### 2.1 High Precision
- The AD421BN series offers exceptional accuracy in converting digital input to 4 - 20 mA current output. It has a low integral nonlinearity (INL) and differential nonlinearity (DNL), ensuring that the output current closely follows the input digital code. This high precision is crucial in industrial applications where even small errors in signal transmission can lead to significant inaccuracies in process control.
- For example, in a chemical processing plant, accurate measurement and control of fluid flow rates are essential for maintaining product quality and safety. The high - precision output of the AD421BN helps ensure that the flow control valves receive the correct signals, resulting in consistent and reliable operation.

### 2.2 Wide Digital Input Range
- It supports a wide range of digital input formats, including serial peripheral interface (SPI). This flexibility allows the AD421BN to be easily integrated with various microcontrollers, digital signal processors, and other digital control devices.
- Designers can choose the most suitable digital communication protocol for their specific application, simplifying the overall system design and reducing development time. For instance, in a distributed control system (DCS), the AD421BN can communicate with multiple control nodes using SPI, enabling seamless data transfer and control.

### 2.3 Low Power Consumption
- In industrial environments, power efficiency is a critical factor, especially in remote or battery - powered applications. The AD421BN series is designed with low power consumption in mind, helping to extend the battery life of portable devices and reduce overall energy costs in fixed installations.
- For example, in a wireless sensor network used for environmental monitoring, the low power consumption of the AD421BN allows the sensors to operate for longer periods without frequent battery replacements, reducing maintenance requirements.

### 2.4 Robustness and Reliability
- The AD421BN is built to withstand harsh industrial environments. It has a wide operating temperature range, typically from - 40°C to + 85°C, and is resistant to electrical noise, electromagnetic interference (EMI), and radio - frequency interference (RFI).
- This robustness ensures reliable operation in industrial settings such as factories, refineries, and power plants, where there are high levels of electrical noise and environmental stress. For example, in a steel mill, the AD421BN can operate reliably in the presence of large motors and electrical equipment that generate significant amounts of EMI.

## 3. Applications

### 3.1 Process Control
- In industrial process control systems, the AD421BN is used to convert digital control signals from a programmable logic controller (PLC) or a distributed control system (DCS) into 4 - 20 mA current signals. These current signals are then used to drive actuators such as valves, motors, and pumps, allowing precise control of process variables.
- For example, in a water treatment plant, the AD421BN can be used to control the flow rate of chemicals into the water treatment process, ensuring that the water quality meets the required standards.

### 3.2 Instrumentation
- The AD42

Images for reference

16-DIP SOT38-1

16-Dip

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Datasheets

• AD421
• PDF 2

Partlist