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[FAQ] Designing with 4-20mA current loop transmitters (XTRs): FAQ links

This post serves as a landing pad for frequently asked questions that arise when designing with 4-20mA current loop transmitters. Keep in mind that there are other common output current ranges such as 0-20mA or 0-24mA, and the ideas presented in the following links can apply to those ranges as well. The information in this post focuses on the theory behind 4-20mA current transmitters, and common questions surrounding TI's XTR current transmitters.

Watch the TI Precision Labs Series on Current Loop Transmitters here:

Video1: Introduction to 4-20mA current loop transmitters

Video2: Current loop transmitters configurations

Video3: Analog Input 2-wire 4-20mA Transmitters

Video4: Analog Input 3-wire 4-20mA Transmitters


General FAQ

What is a 4-20mA current transmitter?

What is a 2-wire 4-20mA current transmitter?

What is a 3-wire 4-20mA current transmitter?

What is a 4-wire 4-20mA current transmitter?

How do I choose a 4-20mA transmitter?

Does TI have integrated 4-20mA transmitters for inputs from RTDs (resistive temperature detectors)?

Does TI have integrated 4-20mA transmitters for inputs from bridge sensors?

Can I use multiple XTR devices if I have multiple DAC outputs or multiple sensors that share a supply and ground?

Are there reference designs that can help me build a 4-20mA transmitter?

What types of applications or end equipment are 4-20mA transmitters used in?


2-wire FAQ

The minimum output current of my 2-wire 4-20mA transmitter is greater than 4mA.

Can I use a 2-wire transmitter with a sensor or microcontroller that uses its own supply?

Why does my 2-wire 4-20mA transmitter output not reach the full 20mA?


3-wire FAQ

When do I need to input isolate a 3-wire transmitter?

Can I use the XTR300 or XTR305 with a single supply?

What is the difference between the XTR300 and XTR305?