**AD420ARZ-32-REEL: Complete Datasheet and Application Circuit Design Guide**

The **AD420ARZ-32-REEL** is a highly precise, **16-bit, serial-input, loop-powered, 4-20 mA current-loop DAC** (Digital-to-Analog Converter) from Analog Devices. Designed for process control and industrial instrumentation, this IC provides a robust and reliable solution for generating an analog current output that is immune to noise over long distances. This article delves into the key specifications from its datasheet and provides a practical application circuit design guide.

**Key Datasheet Specifications and Features**

The AD420 operates from a wide **supply voltage range of +12 V to +36 V**, making it directly compatible with standard 24 V industrial power supplies. Its core functionality is to convert a serial digital input into a highly accurate analog current output. The **"-32"** suffix denotes the specific output range, which in this case is the standard **4 mA to 20 mA**.

* **Resolution:** True 16-bit monotonicity ensures no missing codes and provides exceptional output precision.

* **Accuracy:** The device boasts excellent integral and differential non-linearity (INL/DNL), critical for maintaining signal integrity across the entire output range.

* **Serial Interface:** It supports a flexible **serial data interface** (clock, data, and latch signals) that is compatible with SPI, QSPI, and MICROWIRE protocols, allowing for easy connection to most microcontrollers and digital systems.

* **Loop Power:** As a loop-powered device, the AD420 derives its operating power directly from the same current loop it is modulating, simplifying system design and enhancing reliability in isolated systems.

* **Programmable Output Ranges:** While the -32 version is fixed for 4-20 mA, other variants offer ranges like 0-20 mA and 0-24 mA, providing design flexibility.

* **Package:** The AD420ARZ comes in a 24-lead SOIC package, and the "-REEL" indicates it is supplied on a tape-and-reel for high-volume manufacturing.

**Application Circuit Design Guide**

A typical 4-20 mA current loop transmitter application circuit using the AD420 is shown below. The design focuses on generating a precise, loop-powered output.