High-voltage SAR ADCs deliver high system accuracy for multi-channel industrial applications

DALLAS, TX -- Texas Instruments (TI) expands its successive approximation register (SAR) analog-to-digital converter (ADC) portfolio with the first devices in a new high-voltage family. The eight-channel ADS8688 and four-channel ADS8684 allow input ranges up to +/- 10.24 V to be powered by a single 5-V supply, greatly simplifying system power requirements. They feature the industry's lowest gain drift, offset voltage and offset drift, and the highest precision reference, giving engineers unprecedented levels of accuracy for their designs throughout the full extended industrial temperature range.

The new family of ADCs can improve total system accuracy in a broad range of multi-channel industrial applications, including power automation, low- and medium-voltage relay protection, protection relay monitoring, factory automation equipment and programmable logic controllers (PLCs). For more information about the ADS8688 family, visit www.ti.com/ADS8688-pr.

Key benefits of the ADS8688 family

•No high-voltage supplies needed: Simplifies system design by eliminating the need to generate separate high-voltage supplies. The devices support bipolar input ranges up to +/- 10.24 V and unipolar ranges up to +/- 10.24 V with a single 5-V supply.
•Leading DC error performance: Achieve better than 99.9 percent accuracy without calibration with DC error specifications that boost system-level performance. With specified gain drift of 4 ppm/C and offset drift of 3 ppm/C, the devices eliminate the need for designers to spend time calibrating their systems over temperature ranges.
•Performance across temperature ranges: An integrated precision reference and reference buffer improve low-temperature drift specifications, enabling precision performance without requiring external circuitry across the full extended industrial temperature range of minus 40 C to 125 C.
•High integration for industrial sensor designs: Each device integrates into one chip 20 active devices, including programmable gain amplifiers (PGAs), driver amplifiers, multiplexer, voltage reference, reference buffer and SAR ADC, plus an auxiliary channel input for interfacing straight to the ADC. This integration allows the ADS8688 and ADS8684 to connect directly to various sensor types that require no signal conditioning.

Tools and support to jump-start design

TI offers a range of support tools to speed time to market for designers using the ADS8688 family, including simulation models, hardware evaluation kits and reference designs.

System designers can evaluate the ADS8688 and ADS8684 in a fraction of the time they might spend evaluating other precision ADCs by using a new performance demonstration kit (PDK) that features a simple installation process. The PDK includes an evaluation module (EVM) and simple capture card for plug-and-play functionality, replacing online software installations with a simple one-click process. The kit's intuitive, easy-to-use graphical user interface (GUI) enables designers to quickly evaluate ADC performance in specific end equipment.

The following TI Designs reference designs provide theory, simulation, calculation, design methodology and more:

•Phase-compensated, eight-channel multiplexed data acquisition system for power automation (TIPD167).
•16-bit, eight-channel integrated analog input module for PLCs (TIDA_00164).

Support is available in the Precision Data Converters Forum of the TI E2E™ Community, where engineers can search for solutions, get help, share knowledge and solve problems with fellow engineers and TI experts.

Package, availability and pricing
The ADS8688 family of devices come in a 38-pin, 9.7-mm by 4.4-mm TSSOP package. A datasheet is available at http://www.ti.com/lit/ds/symlink/ads8688.pdf  

Learn more at http://www.ti.com


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