Low Power 4–20mA Sensor Transmitter for Industrial Automation

Create small, low power, and highly accurate designs for industrial automation applications with the MAX12900 ultra-low power, highly integrated 4-20mA sensor transmitter from Maxim Integrated Products, Inc. Target applications include industrial automation and process control, loop-powered 4-20mA current transmitters, remote instrumentation, and smart sensors.

Today, system designers must develop enhanced 4-20mA sensor transmitters with several considerations in mind. These include improved measurement accuracy over a wide temperature range and reduced size to fit in a small enclosure.

In addition, they are required to meet a tight current budget of their overall sensor transmitter system of 4mA maximum. The MAX12900 increases system accuracy with 10ppm/degree C voltage reference for up to 3.5x lower drift compared to traditional solutions.

MAX12900 block diagram (click on image to enlarge)

The small footprint (5mm x 5mm package size) of the MAX12900 integrates 10 optimized building blocks that results in significant space savings of 20%-50% vs. traditional 4-20mA sensor transmitter implementations.

The addition of an integrated high voltage LDO and power sequencing capability simplifies the power up of the 4-20mA sensor transmitter. Its reduced current consumption for low power requires just 250µA of current maximum, enabling up to 50% power savings compared to traditional solutions.

The new MAX12900 solution reduces implementation complexity, generating system cost savings by converting pulse width modulation data from a microcontroller into current over a 4-20mA loop with two, three, or four wire configurations.

The MAX12900 is available in a 32-pin TQFN package and operates over a wide industrial temperature range of -40 to +125 degrees C

Key features

  • Wide Input Supply Range: 4.0V to 36V
  • Ultra-Low-Power Consumption: 170µA (typ)
  • High Linearity: 0.01% (Max Error)
  • High Resolution: Up to 16 Bit
  • Low Drift Voltage Reference: 10ppm/degree C max
  • Wide Temperature Range: -40 to +125 degrees C
  • Small Package: 5mm x 5mm x 0.8mm 32-pin TQFN

“With Maxim’s MAX12900, we now have the flexibility to implement 2- and 3-wire configuration in our solutions,” said Juergen Schmollinger, Group Leader, Development Electronics, Pressure Sensors at IFM. “In addition, we can use it with both a mid and high end 4-20mA transmitter due to its high accuracy.”

“The combination of integration and flexibility, coupled with low power and high accuracy, makes the MAX12900 an ideal solution for low power sensor transmitters and industrial safety applications,” added Carmelo Morello, Executive Business Manager at Maxim Integrated.

Availability and Pricing

  • The MAX12900 is available at Maxim's website and select authorized distributors for $2.89 (1000-up, FOB USA)
  • The MAX12900EVKIT# evaluation kit is available for $55

The MAX12900 evaluation kit (EV kit) provides a proven design to evaluate the MAX12900, loop-powered 4-20mA sensor transmitter. The EV kit includes an evaluation board and a graphical user interface (GUI) that provides communication from a PC to the target device through a USB port.



The EV kit includes Windows® 7, Windows 8, and Windows 10 compatible software for exercising the features of the IC. The EV kit GUI allows to set the Coarse and Fine PWM duty cycle inputs to the MAX12900 to control the 4-20mA loop current with ±1µA resolution.

The EV kit must be powered from an external +24V power supply and consumes less than 2.7mA. The MAX12900 EV kit comes with a MAX12900ATJ+ installed in a 32-pin, 5 x 5mm TQFN-EP package.

Maxim Integrated Products Inc.
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