SBAS633E February   2016  – August 2022 ADS8681 , ADS8685 , ADS8689

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 6 Specifications
    1. 6.1  Absolute Maximum Ratings
    2. 6.2  ESD Ratings
    3. 6.3  Recommended Operating Conditions
    4. 6.4  Thermal Information
    5. 6.5  Electrical Characteristics
    6. 6.6  Timing Requirements: Conversion Cycle
    7. 6.7  Timing Requirements: Asynchronous Reset
    8. 6.8  Timing Requirements: SPI-Compatible Serial Interface
    9. 6.9  Timing Requirements: Source-Synchronous Serial Interface (External Clock)
    10. 6.10 Timing Requirements: Source-Synchronous Serial Interface (Internal Clock)
    11. 6.11 Timing Diagrams
    12. 6.12 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Analog Input Structure
      2. 7.3.2 Analog Input Impedance
      3. 7.3.3 Input Protection Circuit
      4. 7.3.4 Programmable Gain Amplifier (PGA)
      5. 7.3.5 Second-Order, Low-Pass Filter (LPF)
      6. 7.3.6 ADC Driver
      7. 7.3.7 Reference
        1. 7.3.7.1 Internal Reference
        2. 7.3.7.2 External Reference
      8. 7.3.8 ADC Transfer Function
      9. 7.3.9 Alarm Features
        1. 7.3.9.1 Input Alarm
        2. 7.3.9.2 AVDD Alarm
    4. 7.4 Device Functional Modes
      1. 7.4.1 Host-to-Device Connection Topologies
        1. 7.4.1.1 Single Device: All multiSPI Options
        2. 7.4.1.2 Single Device: Standard SPI Interface
        3. 7.4.1.3 Multiple Devices: Daisy-Chain Topology
      2. 7.4.2 Device Operational Modes
        1. 7.4.2.1 RESET State
        2. 7.4.2.2 ACQ State
        3. 7.4.2.3 CONV State
    5. 7.5 Programming
      1. 7.5.1 Data Transfer Frame
      2. 7.5.2 Input Command Word and Register Write Operation
      3. 7.5.3 Output Data Word
      4. 7.5.4 Data Transfer Protocols
        1. 7.5.4.1 Protocols for Configuring the Device
        2. 7.5.4.2 Protocols for Reading From the Device
          1. 7.5.4.2.1 Legacy, SPI-Compatible (SYS-xy-S) Protocols with a Single SDO-x
          2. 7.5.4.2.2 Legacy, SPI-Compatible (SYS-xy-S) Protocols With Dual SDO-x
          3. 7.5.4.2.3 Source-Synchronous (SRC) Protocols
            1. 7.5.4.2.3.1 Output Clock Source Options
            2. 7.5.4.2.3.2 Output Bus Width Options
    6. 7.6 Register Maps
      1. 7.6.1 Device Configuration and Register Maps
        1. 7.6.1.1 DEVICE_ID_REG Register (address = 00h)
        2. 7.6.1.2 RST_PWRCTL_REG Register (address = 04h)
        3. 7.6.1.3 SDI_CTL_REG Register (address = 08h)
        4. 7.6.1.4 SDO_CTL_REG Register (address = 0Ch)
        5. 7.6.1.5 DATAOUT_CTL_REG Register (address = 10h)
        6. 7.6.1.6 RANGE_SEL_REG Register (address = 14h)
        7. 7.6.1.7 ALARM_REG Register (address = 20h)
        8. 7.6.1.8 ALARM_H_TH_REG Register (address = 24h)
        9. 7.6.1.9 ALARM_L_TH_REG Register (address = 28h)
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
      3. 8.2.3 Application Curves
    3. 8.3 Power Supply Recommendations
      1. 8.3.1 Power Supply Decoupling
      2. 8.3.2 Power Saving
        1. 8.3.2.1 NAP Mode
        2. 8.3.2.2 Power-Down (PD) Mode
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
  9. 9 Device and Documentation Support
    1. 9.1 Documentation Support
      1. 9.1.1 Related Documentation
    2. 9.2 Receiving Notification of Documentation Updates
    3. 9.3 Support Resources
    4. 9.4 Trademarks
    5. 9.5 Electrostatic Discharge Caution
    6. 9.6 Glossary
  10. 10Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • PW|16
  • RUM|16
Thermal pad, mechanical data (Package|Pins)
Orderable Information

5 Pin Configuration and Functions

GUID-6AFEB4F1-CA11-416E-8438-8CA14DA605F9-low.gifFigure 5-1 PW Package,16-Pin TSSOP
(Top View, Not to Scale)
GUID-22664DC4-E733-42B6-9A04-D76B60CCCE45-low.gifFigure 5-2 RUM Package,16-Pin WQFN
(Top View, Not to Scale)
Table 5-1 Pin Functions
NAME NO. TYPE(1) DESCRIPTION
TSSOP WQFN
AGND 3 1 P Analog ground pin. Decouple with the AVDD pin.
AIN_GND 8 6 AI Analog input: negative. Decouple with the AIN_P pin.
AIN_P 7 5 AI Analog input: positive. Decouple with the AIN_GND pin.
ALARM/SDO-1/GPO 14 12 DO Multifunction output pin. Active high alarm.
Data output 1 for serial communication. General-purpose output pin.
AVDD 2 16 P Analog supply pin. Decouple with the AGND pin.
CONVST/CS 11 9 DI Dual-functionality pin.
Active high logic: conversion start input pin; a CONVST rising edge brings the device from acquisition phase to conversion phase.
Active low logic: chip-select input pin; the device takes control of the data bus when CS is low; the SDO-x pins go to tri-state when CS is high.
DGND 1 15 P Digital ground pin. Decouple with the DVDD pin.
DVDD 16 14 P Digital supply pin. Decouple with the DGND pin.
REFCAP 6 4 AO ADC reference buffer decoupling capacitor pin. Decouple with the REFGND pin.
REFGND 5 3 P Reference ground pin; short to the analog ground plane. Decouple with the REFIO and REFCAP pins.
REFIO 4 2 AIO Internal reference output and external reference input pin. Decouple with REFGND.
RST 9 7 DI Active low logic input to reset the device.
RVS 15 13 DO Multifunction output pin for serial interface; see the Section 7.4.2.1 section.
With CS held high, RVS reflects the status of the internal ADCST signal.
With CS low, the status of RVS depends on the output protocol selection.
SCLK 12 10 DI Serial communication: clock input pin for the serial interface.
All system-synchronous data transfer protocols are timed with respect to the SCLK signal.
SDI 10 8 DI Dual function: data input pin for serial communication.
Chain data input during serial communication in daisy-chain mode.
SDO-0 13 11 DO Serial communication: data output 0
(1) AI = analog input, AIO = analog input/output, DI = digital input, DO = digital output, and P = power supply.