TI Releases 4-20mA DAC with Integrated Buck/Boost Converter
New DAC8775 Precision Data Converter operates from a single supply and is housed in a miniature QFN Package
Texas Instruments has 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.
Features of the DAC8775 Data Converter include:
- 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.
Technical Specifications of the DAC8775
- Output Current:
- 0 mA to 24 mA
- 3.5 mA to 23.5 mA
- 0 mA to 20 mA
- 4 mA to 20 mA
- ±24 mA
- Output Voltage:
- 0 V to 5 V; 0 V to 10 V; ±5 V; ±10 V
- 0 V to 6 V; 0 V to 12 V; ±6 V; ±12 V
- Adaptive Power Management
- Single Wide Power Supply Pin (12 V – 36 V)
- ±0.1% FSR Total Unadjusted Error (TUE)
- DNL: ±1 LSB Max
- Internal 5-V Reference (10 ppm/°C max)
- Internal 5-V Digital Power Supply Output
- CRC/Frame Error Check, Watchdog Timer
- Thermal Alarm, Open/Short Circuit for System Reliability
- Safe Actions on Alarm Condition
- Auto Learn Load Detection
- Wide Temperature Range: –40°C to +125°C
More information on the DAC8775 Precision Data Converter, can be found on the TI Web site
TI DAC8775 product page
The company's Web site address is www.ti.com
[Reprinted with kind permission from Texas Instruments - Release Date, 8th March, 2017]