16-Bit 500kSPS 8-Ch SAR ADC With Bipolar Inputs Using 5V Supply and Low-Drift Vref
Product details
Parameters
Package | Pins | Size
Features
- 16-Bit ADCs with Integrated Analog Front-End
- 4-, 8-Channel MUX with Auto and Manual Scan
- Channel-Independent Programmable Inputs:
- ±10.24 V, ±5.12 V, ±2.56 V, ±1.28 V, ±0.64 V
- 10.24 V, 5.12 V, 2.56 V, 1.28 V
- 5-V Analog Supply: 1.65-V to 5-V I/O Supply
- Constant Resistive Input Impedance: 1 MΩ
- Input Overvoltage Protection: Up to ±20 V
- On-Chip, 4.096-V Reference with Low Drift
- Excellent Performance:
- 500-kSPS Aggregate Throughput
- DNL: ±0.5 LSB; INL: ±0.75 LSB
- Low Drift for Gain Error and Offset
- SNR: 92 dB; THD: –102 dB
- Low Power: 65 mW
- AUX Input → Direct Connection to ADC Inputs
- ALARM → High and Low Thresholds per Channel
- SPI™-Compatible Interface with Daisy-Chain
- Industrial Temperature Range: –40°C to 125°C
- TSSOP-38 Package (9.7 mm × 4.4 mm)
Description
The ADS8684A and ADS8688A are 4- and 8-channel, integrated data acquisition systems based on a 16-bit successive approximation (SAR) analog-to-digital converter (ADC), operating at a throughput of 500 kSPS. The devices feature integrated analog front-end circuitry for each input channel with overvoltage protection up to ±20 V, a 4- or 8-channel multiplexer with automatic and manual scanning modes, and an on-chip, 4.096-V reference with low temperature drift. Operating on a single 5-V analog supply, each input channel on the devices can support true bipolar input ranges of ±10.24 V, ±5.12 V, ±2.56 V, ±1.28V and ±0.64V, as well as unipolar input ranges of 0 V to 10.24 V, 0 V to 5.12 V, 0 V to 2.56 V and 0 V to 1.28 V. The gain of the analog front-end for all input ranges is accurately trimmed to ensure a high dc precision. The input range selection is software-programmable and independent for each channel. The devices offer a 1-MΩ constant resistive input impedance irrespective of the selected input range.
The ADS8684A and ADS8688A offer a simple SPI-compatible serial interface to the digital host and also support daisy-chaining of multiple devices. The digital supply operates from 1.65 V to 5.25 V, enabling direct interface to a wide range of host controllers.
Technical documentation
= Top documentation for this product selected by TI
| Type | Title | Date | |
|---|---|---|---|
| * | Datasheet | ADS868xA 16-Bit, 500-kSPS, 4- and 8-Channel, Single-Supply, SAR ADCs with Bipolar Input Ranges datasheet | Jul. 14, 2015 |
| Application note | Supporting High Voltage Common Mode Using Instrumentational Amplifier | Feb. 23, 2021 | |
| Application note | Reducing Phase Delay by Averaging on ADS8686S with Burst Sequencer Mode | Jan. 11, 2021 | |
| Application note | 16-Bit 8-Channel PLC Analog Input Module with High Voltage (±150 V) Common Mode | Apr. 27, 2020 | |
| Application note | Input protection for high-voltage ADC circuit with TVS diode | Jun. 26, 2019 | |
| Application note | High common-mode differential input voltage to ±10-V ADC input circuit | Dec. 20, 2018 | |
| Application note | Extending Input Voltage Range and Understanding Associated Errors for ADC With I | Nov. 09, 2018 | |
| White paper | Voltage-reference impact on total harmonic distortion | Aug. 01, 2016 | |
| User guide | ADS86xxEVM-PDK Evaluation Module (Rev. A) | Jul. 17, 2015 | |
| E-book | Best of Baker's Best: Precision Data Converters -- SAR ADCs | May 21, 2015 |
Design & development
For additional terms or required resources, click any title below to view the detail page where available.Design tools & simulation
SBAM199.ZIP (37 KB) - IBIS Model
SBAM201.ZIP (1597 KB) - TINA-TI Reference Design
PSPICE-FOR-TI — PSpice® for TI is a design and simulation environment that helps evaluate functionality of analog circuits. This full-featured, design and simulation suite uses an analog analysis engine from Cadence®. Available at no cost, PSpice for TI includes one of the largest model libraries in the (...)
Features
- Leverages Cadence PSpice Technology
- Preinstalled library with a suite of digital models to enable worst-case timing analysis
- Dynamic updates ensure you have access to most current device models
- Optimized for simulation speed without loss of accuracy
- Supports simultaneous analysis of multiple products
- (...)
TINA-TI — TINA-TI provides all the conventional DC, transient and frequency domain analysis of SPICE and much more. TINA has extensive post-processing capability that allows you to format results the way you want them. Virtual instruments allow you to select input waveforms and probe circuit nodes voltages (...)
ADC-INPUT-CALC — ADC-INPUT-CALC is an online tool that provides support for designing the input buffer to an analog-to-digital converter (ADC). It offers 24 different op-amp based buffer circuits that can be used to drive an ADC input. The available topologies cover differential, single-ended and transformer-coupled (...)
ANALOG-ENGINEER-CALC — The Analog Engineer’s Calculator is designed to speed up many of the repetitive calculations that analog circuit design engineers use on a regular basis. This PC-based tool provides a graphical interface with a list of various common calculations ranging from setting op-amp gain with feedback (...)
Features
- Expedites circuit design with analog-to-digital converters (ADCs) and digital-to-analog converters (DACs)
- Noise calculations
- Common unit translation
- Solves common amplifier circuit design problems
- Gain selections using standard resistors
- Filter configurations
- Total noise for common amplifier configurations
- (...)
Reference designs
TIDA-01576 — This reference design accurately measures 16-channel AC voltage and current inputs using a precision 16-bit SAR ADC over a wide input range. This range covers protection and measurement requirements (including sampling requirements as per IEC 61850-9-2), which simplifies system design and improves (...)
Design files
TIDA-01214 — This reference design provides accurate measurements of AC voltage and current inputs using a precision 16-bit SAR ADC over a wide input range, covering protection and measurement range (including sampling requirements of IEC 61850-9-2), simplifying system design and improving trip time performance (...)
Design files
-
download TIDA-01214 BOM Files.zip (520KB) -
download TIDA-01214 Assembly Files.zip (716KB) -
download TIDA-01214 Layer Plots.zip (4008KB) -
download TIDA-01214 Altium.zip (7943KB) -
download TIDA-01214 Gerber.zip (2975KB)
CAD/CAE symbols
| Package | Pins | Download |
|---|---|---|
| TSSOP (DBT) | 38 | View options |
Ordering & quality
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- MTBF/FIT estimates
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