SBAS843A september   2017  – july 2023 ADS8588H

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Revision History
  6. 5 Pin Configuration and Functions
  7. 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: CONVST Control
    7. 6.7  Timing Requirements: Data Read Operation
    8. 6.8  Timing Requirements: Parallel Data Read Operation, CS and RD Tied Together
    9. 6.9  Timing Requirements: Parallel Data Read Operation, CS and RD Separate
    10. 6.10 Timing Requirements: Serial Data Read Operation
    11. 6.11 Timing Requirements: Byte Mode Data Read Operation
    12. 6.12 Timing Requirements: Oversampling Mode
    13. 6.13 Timing Requirements: Exit Standby Mode
    14. 6.14 Timing Requirements: Exit Shutdown Mode
    15. 6.15 Switching Characteristics: CONVST Control
    16. 6.16 Switching Characteristics: Parallel Data Read Operation, CS and RD Tied Together
    17. 6.17 Switching Characteristics: Parallel Data Read Operation, CS and RD Separate
    18. 6.18 Switching Characteristics: Serial Data Read Operation
    19. 6.19 Switching Characteristics: Byte Mode Data Read Operation
    20. 6.20 Timing Diagrams
    21. 6.21 Typical Characteristics
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  Analog Inputs
      2. 7.3.2  Analog Input Impedance
      3. 7.3.3  Input Clamp Protection Circuit
      4. 7.3.4  Programmable Gain Amplifier (PGA)
      5. 7.3.5  Third-Order, Low-Pass Filter (LPF)
      6. 7.3.6  ADC Driver
      7. 7.3.7  Digital Filter and Noise
      8. 7.3.8  Reference
        1. 7.3.8.1 Internal Reference
        2. 7.3.8.2 External Reference
        3. 7.3.8.3 Supplying One VREF to Multiple Devices
      9. 7.3.9  ADC Transfer Function
      10. 7.3.10 ADS8588H Device Family Comparison
    4. 7.4 Device Functional Modes
      1. 7.4.1 Device Interface: Pin Description
        1. 7.4.1.1  REFSEL (Input)
        2. 7.4.1.2  RANGE (Input)
        3. 7.4.1.3  STBY (Input)
        4. 7.4.1.4  PAR/SER/BYTE SEL (Input)
        5. 7.4.1.5  CONVSTA, CONVSTB (Input)
        6. 7.4.1.6  RESET (Input)
        7. 7.4.1.7  RD/SCLK (Input)
        8. 7.4.1.8  CS (Input)
        9. 7.4.1.9  OS[2:0]
        10. 7.4.1.10 BUSY (Output)
        11. 7.4.1.11 FRSTDATA (Output)
        12. 7.4.1.12 DB15/BYTE SEL
        13. 7.4.1.13 DB14/HBEN
        14. 7.4.1.14 DB[13:9]
        15. 7.4.1.15 DB8/DOUTB
        16. 7.4.1.16 DB7/DOUTA
        17. 7.4.1.17 DB[6:0]
      2. 7.4.2 Device Modes of Operation
        1. 7.4.2.1 Power-Down Modes
          1. 7.4.2.1.1 Standby Mode
          2. 7.4.2.1.2 Shutdown Mode
        2. 7.4.2.2 Conversion Control
          1. 7.4.2.2.1 Simultaneous Sampling on All Input Channels
          2. 7.4.2.2.2 Simultaneous Sampling Two Sets of Input Channels
        3. 7.4.2.3 Data Read Operation
          1. 7.4.2.3.1 Parallel Data Read
          2. 7.4.2.3.2 Parallel Byte Data Read
          3. 7.4.2.3.3 Serial Data Read
          4. 7.4.2.3.4 Data Read During Conversion
        4. 7.4.2.4 Oversampling Mode of Operation
  9. 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 Curve
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Examples
  10. 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
  11. 10Mechanical, Packaging, and Orderable Information

Package Options

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

7.3.7 Digital Filter and Noise

The ADS8588H features an optional digital averaging filter that can be used in slower throughput applications requiring lower noise and higher dynamic range. As explained in Table 7-1, the oversampling ratio of the digital filter is determined by the configuration of the OS[2:0] pins. The overall throughput of the ADC decreases proportionally with increases in the oversampling ratio.

Table 7-1 Oversampling Bit Decoding
OS[2:0] OS RATIO SNR
±10-V INPUT
(dB)		 SNR
±5-V INPUT
(dB)		 3-dB BANDWIDTH
±10-V INPUT
(kHz)		 3-dB BANDWIDTH
±5-V INPUT
(kHz)		 MAX THROUGHPUT PER CHANNEL
(kSPS)
000 No OS 92.7 92.2 24 16 500
001 2 93.4 92.7 23.9 15.9 250
010 4 94.0 93.2 23.2 15.7 125
011 8 94.7 93.7 20.6 14.9 62.5
100 16 95.8 94.5 13.7 12.2 31.25
101 32 96.9 95.8 7 6.9 15.625
110 64 98.3 97.4 3.5 3.5 7.8125
111 Invalid — — — — —

In oversampling mode (see the Oversampling Mode of Operation section), the ADC takes the first sample for each channel at the rising edge of the CONVSTA, CONVSTB signals. After converting the first sample, the subsequent samples are taken by an internally generated sampling control signal. The samples are then averaged to reduce the noise of the signal chain as well as to improve the SNR of the ADC. The final output is also decimated to provide a 16-bit output for each channel. Table 7-1 lists the typical SNR performance for both the ±10-V and ±5-V input ranges, including the –3-dB bandwidth and proportional maximum throughput per channel. When the oversampling ratio increases, there is a proportional improvement in the SNR performance and decrease in the bandwidth of the input filter.