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Ultra-Low-Power 4-20mA Sensor Transmitter

Less than 200µA in a Small 5mm x 5mm Package

Product Details

Key Features

Applications/Uses

Simplified Block Diagram

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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/°C max
  • Wide Temperature Range: -40°C to +125°C
  • Small Package: 5mm x 5mm x 0.8mm 32-pin TQFN

Applications/Uses

  • Industrial Automation and Process Control
  • Loop-powered 4-20mA Current Transmitter
  • Remote Instrumentation
  • Smart Sensors

Description

The MAX12900 is an ultra-low-power, highly integrated 4-20mA sensor transmitter. The MAX12900 integrates ten building blocks in a small package: a wide input supply voltage LDO, two conditioner circuits for pulse-width modulated (PWM) inputs, two low-power, low-drift, general purpose operational amplifiers (op amp) one wide bandwidth, zero-offset drift operational amplifier; two diagnostic comparators, a power-up sequencer with power good output to allow for a smooth power-up, and a low-drift voltage reference.

The MAX12900 converts PWM data from a microcontroller into current over a 4-20mA loop with two, three, or four wire configurations.

The equivalent to an ultra-low-power, high-resolution, digital-to-analog converter is realized with the combination of two-PWM signals received from a microcontroller, the two conditioner circuits, and an active filter built with the integrated low-power op amp. The outputs of the two conditioner circuits provide a stable PWM amplitude over voltage supply and temperature variation. The wide bandwidth amplifier, in combination with a discrete transistor, converts a voltage input into a current output and allows HART and Foundation Fieldbus H1 signal modulation. The zero-offset operational amplifier and the low-drift voltage reference provide negligible error over wide temperature. The low-power operational amplifier and comparators provide building blocks for enhanced diagnostic features. Supply rail monitoring, output current readback, open circuit and failure detection are a few examples of diagnostic features. All these features, as well as ultra-low-power and high accuracy make the MAX12900 ideal for loop-powered smart sensor transmitters for industrial application.

The MAX12900 is available in 5mm x 5mm 32-pin TQFN package and operates over a wide industrial temperature range of -40°C to +125°C.

Simplified Block Diagram

MAX12900: Functional Block Diagram MAX12900: Functional Block Diagram Zoom icon

Technical Docs

Support & Training

Search our knowledge base for answers to your technical questions.

Filtered Search

Our dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal .