SBAS773A September   2017  – December 2017 ADS7142

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 - All Modes
    6. 6.6  Electrical Characteristics - Manual Mode
    7. 6.7  Electrical Characteristics - Autonomous Modes
    8. 6.8  Electrical Characteristics - High Precision Mode
    9. 6.9  Timing Requirements
    10. 6.10 Switching Characteristics
    11. 6.11 Typical Characteristics for All Modes
    12. 6.12 Typical Characteristics for Manual Mode
    13. 6.13 Typical Characteristics for Autonomous Modes
    14. 6.14 Typical Characteristics for High Precision Mode
  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 and Multiplexer
        1. 7.3.1.1 Two-Channel, Single-Ended Configuration
        2. 7.3.1.2 Single-Channel, Single-Ended Configuration
        3. 7.3.1.3 Single-Channel, Pseudo-Differential Configuration
      2. 7.3.2  OFFSET Calibration
      3. 7.3.3  Reference
      4. 7.3.4  ADC Transfer Function
      5. 7.3.5  Oscillator and Timing Control
      6. 7.3.6  I2C Address Selector
      7. 7.3.7  Data Buffer
        1. 7.3.7.1 Filling of the Data Buffer
        2. 7.3.7.2 Reading data from the Data Buffer
      8. 7.3.8  Accumulator
      9. 7.3.9  Digital Window Comparator
      10. 7.3.10 I2C Protocol Features
        1. 7.3.10.1 General Call
        2. 7.3.10.2 General Call with Software Reset
        3. 7.3.10.3 General Call with Write Software programmable part of slave address
        4. 7.3.10.4 Configuring Device into High Speed I2C mode
        5. 7.3.10.5 Bus Clear
      11. 7.3.11 Device Programming
        1. 7.3.11.1 Reading Registers
          1. 7.3.11.1.1 Single Register Read
          2. 7.3.11.1.2 Reading a Continuous Block of Registers
        2. 7.3.11.2 Writing Registers
          1. 7.3.11.2.1 Single Register Write
          2. 7.3.11.2.2 Set Bit
          3. 7.3.11.2.3 Clear Bit
          4. 7.3.11.2.4 Writing a continuous block of registers
    4. 7.4 Device Functional Modes
      1. 7.4.1 Device Power Up and Reset
      2. 7.4.2 Manual Mode
        1. 7.4.2.1 Manual Mode with CH0 Only
        2. 7.4.2.2 Manual Mode with AUTO Sequence
      3. 7.4.3 Autonomous Modes
        1. 7.4.3.1 Autonomous Mode with Threshold Monitoring and Diagnostics
          1. 7.4.3.1.1 Autonomous Mode with Pre Alert Data
          2. 7.4.3.1.2 Autonomous Mode with Post Alert Data
        2. 7.4.3.2 Autonomous Mode with Burst Data
          1. 7.4.3.2.1 Autonomous Mode with Start Burst
          2. 7.4.3.2.2 Autonomous Mode with Stop Burst
      4. 7.4.4 High Precision Mode
    5. 7.5 Optimizing Power Consumed by the Device
    6. 7.6 Register Map
      1. 7.6.1 RESET REGISTERS
        1. 7.6.1.1 WKEY Register (address = 17h), [reset = 00h]
        2. 7.6.1.2 DEVICE_RESET Register (address = 14h), [reset = 00h]
      2. 7.6.2 FUNCTIONAL MODE SELECT REGISTERS
        1. 7.6.2.1 OFFSET_CAL Register (address = 15h), [reset = 00h]
        2. 7.6.2.2 OPMODE_SEL Register (address = 1Ch), [reset = 00h]
        3. 7.6.2.3 OPMODE_I2CMODE_STATUS Register (address = 00h), [reset = 00h]
      3. 7.6.3 INPUT CONFIG REGISTER
        1. 7.6.3.1 CHANNEL_INPUT_CFG Register (address = 24h), [reset = 00h]
      4. 7.6.4 ANALOG MUX and SEQUENCER REGISTERS
        1. 7.6.4.1 AUTO_SEQ_CHEN Register (address = 20h), [reset = 03h]
        2. 7.6.4.2 START_SEQUENCE Register (address = 1Eh), [reset = 00h]
        3. 7.6.4.3 ABORT_SEQUENCE Register (address = 1Fh), [reset = 00h]
        4. 7.6.4.4 SEQUENCE_STATUS Register (address = 04h), [reset = 00h]
      5. 7.6.5 OSCILLATOR and TIMING CONTROL REGISTERS
        1. 7.6.5.1 OSC_SEL Register (address = 18h), [reset = 00h]
        2. 7.6.5.2 nCLK_SEL Register (address = 19h), [reset = 00h]
      6. 7.6.6 DATA BUFFER CONTROL REGISTER
        1. 7.6.6.1 DATA_BUFFER_OPMODE Register (address = 2Ch), [reset = 01h]
        2. 7.6.6.2 DOUT_FORMAT_CFG Register (address = 28h), [reset = 00h]
        3. 7.6.6.3 DATA_BUFFER_STATUS Register (address = 01h), [reset = 00h]
      7. 7.6.7 ACCUMULATOR CONTROL REGISTERS
        1. 7.6.7.1 ACC_EN Register (address = 30h), [reset = 00h]
        2. 7.6.7.2 ACC_CH0_LSB Register (address = 08h), [reset = 00h]
        3. 7.6.7.3 ACC_CH0_MSB Register (address = 09h), [reset = 00h]
        4. 7.6.7.4 ACC_CH1_LSB Register (address = 0Ah), [reset = 00h]
        5. 7.6.7.5 ACC_CH1_MSB Register (address = 0Bh), [reset = 00h]
        6. 7.6.7.6 ACCUMULATOR_STATUS Register (address = 02h), [reset = 00h]
      8. 7.6.8 DIGITAL WINDOW COMPARATOR REGISTERS
        1. 7.6.8.1  ALERT_DWC_EN Register (address = 37h), [reset = 00h]
        2. 7.6.8.2  ALERT_CHEN (address = 34h), [reset = 00h]
        3. 7.6.8.3  DWC_HTH_CH0_MSB Register (address = 39h), [reset = 00h]
        4. 7.6.8.4  DWC_HTH_CH0_LSB Register (address = 38h), [reset = 00h]
        5. 7.6.8.5  DWC_LTH_CH0_MSB Register (address = 3Bh), [reset = 00h]
        6. 7.6.8.6  DWC_LTH_CH0_LSB Register (address = 3Ah), [reset = 00h]
        7. 7.6.8.7  DWC_HYS_CH0 (address = 40h), [reset = 00h]
        8. 7.6.8.8  DWC_HTH_CH1_MSB Register (address = 3Dh), [reset = 00h]
        9. 7.6.8.9  DWC_HTH_CH1_LSB Register (address = 3Ch), [reset = 00h]
        10. 7.6.8.10 DWC_LTH_CH1_MSB Register (address = 3Fh), [reset = 00h]
        11. 7.6.8.11 DWC_LTH_CH1_LSB Register (address = 3Eh), [reset = 00h]
        12. 7.6.8.12 DWC_HYS_CH1 (address = 41h), [reset = 00h]
        13. 7.6.8.13 PRE_ALT_MAX_EVENT_COUNT Register (address = 36h), [reset = 00h]
        14. 7.6.8.14 ALERT_TRIG_CHID Register (address = 03h), [reset = 00h]
        15. 7.6.8.15 ALERT_LOW_FLAGS Register (address = 0C), [reset = 00h]
        16. 7.6.8.16 ALERT_HIGH_FLAGS Register (address = 0Eh), [reset = 00h]
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 ADS7142 as a Programmable Comparator with False Trigger Prevention and Diagnostics
        1. 8.2.1.1 Design Requirements
          1. 8.2.1.1.1 Higher Power Consumption
          2. 8.2.1.1.2 Fixed Threshold Voltages
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1 Programmable Thresholds and Hysteresis
          2. 8.2.1.2.2 False Trigger Prevention with Event Counter
          3. 8.2.1.2.3 Fault Diagnostics with Data Buffer
        3. 8.2.1.3 Application Curve
      2. 8.2.2 Event-triggered PIR sensing with ADS7142
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Detailed Design Procedure
        3. 8.2.2.3 Application Curves
  9. 9 Power-Supply Recommendations
    1. 9.1 AVDD and DVDD Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Community Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

10 Layout

10.1 Layout Guidelines

Figure 124 shows a board layout example for the circuit illustrated in Figure 123. The key considerations for layout are:

  • Use a solid ground plane underneath the device and partition the PCB into analog and digital sections.
  • Avoid crossing digital lines with the analog signal path and keep the analog input signals and the reference input signals away from noise sources.
  • The power sources to the device must be clean and well-bypassed. Use CAVDD decoupling capacitors in close proximity to the analog (AVDD) power supply pin.
  • Use a CDVDD decoupling capacitor close to the digital (DVDD) power-supply pin.
  • Avoid placing vias between the AVDD and DVDD pins and the bypass capacitors.
  • Connect the ground pin to the ground plane using a short, low-impedance path.
  • Place the charge kickback filter components close to the device.
Among ceramic surface-mount capacitors, COG (NPO) ceramic capacitors are recommended because these components provide the most stable electrical properties over voltage, frequency, and temperature changes.

10.2 Layout Example

ADS7142 sch_layout_sbas773.gif Figure 123. Example Circuit
ADS7142 layout_sbas773.png Figure 124. Example Layout