TI introduces industry’s first 4-20mA DAC with integrated buck/boost converter that operates off of a single-supply

Texas Instruments (TI) (NASDAQ:TXN) today introduced a digital-to-analog converter (DAC) that combines industry-leading precision performance with simpler power-supply design. The 16-bit DAC8775 operates from a single, wide 12- to 36-V power rail, leveraging an integrated buck/boost converter to generate all of the required internal power supplies to save designers time, cost and significant board space.

The four-channel DAC8775 addresses the trend in factory automation and process control equipment toward input/output (I/O) modules that must squeeze more channels into a smaller space. Engineers designing these systems face the challenge of managing power dissipation in a small form factor. By combining a 4-20mA current and voltage driver with a precision reference and a buck/boost converter, the DAC8775 enables a total system footprint that is up to 25 percent smaller than the nearest competing device. Expanding TI’s versatile portfolio of precision data converters, this highly integrated DAC can deliver smaller and more efficient designs with advanced diagnostic capabilities.

Key features and benefits of the DAC8775 data converter

• More reliable system design: The DAC8775’s on-chip diagnostic features include smart alarms that monitor open load, short circuit, over-temperature, cyclic redundancy check (CRC), watchdog timer and compliance voltage. Designers can choose preset actions that help detect faults early to facilitate reliable system operation.
• Efficiency with fast response times: The device has an innovative auto-learn feature that calculates the load impedance on the 4-20mA loop and clamps the power supply. This enables faster settling time, balancing efficiency with quicker system response.
• High DC performance: A total unadjusted error of 0.1 percent full-scale range (FSR) over an extended industrial temperature range of -40°C to 125°C enables designers to rate their output modules for higher temperature ranges. The DAC8775’s high DC performance reduces the need for system calibration, saving manufacturing costs compared to a discrete solution.
• Thermally optimized design: The DAC8775 dynamically adjusts the generated supply based on the current load on the 4-20mA loop. This creates an efficient system with well-controlled thermal performance, allowing more channels in a smaller space.

Tools and support to jump-start design
A four-channel analog output module reference design demonstrates the combination of the DAC8775 and the LM5166 high-efficiency synchronous buck converter that dissipates less than 1 W of power in factory-automation implementations. Additionally, an evaluation module is available for US$149 for designers to simulate and optimize the DAC8775.

Availability and pricing
The DAC8775 is available now through the TI store and authorized distributors. The device comes in a 10-mm-by-10-mm quad-flat no-lead (QFN) package and is priced at US$15.72 in 1,000-unit quantities.