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ADS8688A

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16-bit, 500-kSPS, 8-channel SAR ADC with bipolar inputs using 5-V supply and low-drift VREF

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16-bit, 500-kSPS, 8-channel SAR ADC with bipolar inputs using 5-V supply and low-drift VREF

ADS8688A

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Data sheet Order now

Product details

Parameters

Resolution (Bits) 16 Number of input channels 8 Sample rate (Max) (kSPS) 500 Interface type SPI Architecture SAR Input type Single-Ended Multi-channel configuration Multiplexed Rating Catalog Reference mode Ext, Int Input range (Max) (V) 10.24 Input range (Min) (V) -10.24 Features Daisy-Chainable, Oscillator, Over-Voltage Protection, PGA Operating temperature range (C) -40 to 125 Power consumption (Typ) (mW) 65 Analog voltage AVDD (Min) (V) 4.75 SNR (dB) 92 Analog voltage AVDD (Max) (V) 5.25 INL (Max) (+/-LSB) 2 Digital supply (Min) (V) 1.65 Digital supply (Max) (V) 5.25 open-in-new Find other Precision ADCs (<=10MSPS)

Package | Pins | Size

TSSOP (DBT) 38 43 mm² 9.7 x 4.4 open-in-new Find other Precision ADCs (<=10MSPS)

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)
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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.

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Technical documentation

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Type Title Date
* Data sheet ADS868xA 16-Bit, 500-kSPS, 4- and 8-Channel, Single-Supply, SAR ADCs with Bipolar Input Ranges datasheet Jul. 14, 2015
Application note Circuit for detecting input floating on ADS8681 ADC Mar. 31, 2021
Application note Supporting High Voltage Common Mode Using Difference Amplifier Mar. 08, 2021
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
E-book Best of Baker's Best: Precision Data Converters -- SAR ADCs May 21, 2015
User guide Phase-Compensated 8-Ch Multiplexed Data Acquisition System for Power Automation (Rev. B) Mar. 12, 2015

Design & development

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Design tools & simulation

SIMULATION MODEL Download
SBAM199.ZIP (37 KB) - IBIS Model
SIMULATION MODEL Download
SBAM201.ZIP (1597 KB) - TINA-TI Reference Design
SIMULATION TOOL Download
PSpice® for TI design and simulation tool
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
  • (...)
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SIMULATION TOOL Download
SPICE-based analog simulation program
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 (...)
document-generic User guide
CALCULATION TOOL Download
Analog-to-digital converter (ADC) input driver design tool supporting multiple input types
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 (...)
CALCULATION TOOL Download
Analog engineer's calculator
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
  • (...)
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Reference designs

REFERENCE DESIGNS Download
High accuracy analog input module reference design with 16-bit 1-MSPS dual simultaneous-sampling ADC
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 (...)
document-generic Schematic
REFERENCE DESIGNS Download
Isolated, High-Accuracy Analog Input Module Reference Design Using 16-Bit ADC and Digital Isolator
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 (...)
document-generic Schematic

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TSSOP (DBT) 38 View options

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