ZHCSSI3 February   2024 ADS1288

PRODUCTION DATA  

  1.   1
  2. 1 特性
  3. 2 应用
  4. 3 说明
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information
    5. 5.5 Electrical Characteristics
    6. 5.6 Timing Requirements: 1.65V ≤ IOVDD ≤ 1.95V and 2.7V ≤ IOVDD ≤ 3.6V
    7. 5.7 Switching Characteristics: 1.65V ≤ IOVDD ≤ 1.95V and 2.7V ≤ IOVDD ≤ 3.6V
    8. 5.8 Timing Diagrams
    9. 5.9 Typical Characteristics
  7. 6 Parameter Measurement Information
    1. 6.1 Noise Performance
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Analog Input
      2. 7.3.2 PGA and Buffer
        1. 7.3.2.1 Programmable Gain Amplifier (PGA)
        2. 7.3.2.2 Buffer Operation (PGA Bypass)
      3. 7.3.3 Voltage Reference Input
      4. 7.3.4 IOVDD Power Supply
      5. 7.3.5 Modulator
        1. 7.3.5.1 Modulator Overdrive
      6. 7.3.6 Digital Filter
        1. 7.3.6.1 Sinc Filter Section
        2. 7.3.6.2 FIR Filter Section
        3. 7.3.6.3 Group Delay and Step Response
          1. 7.3.6.3.1 Linear Phase Response
          2. 7.3.6.3.2 Minimum Phase Response
        4. 7.3.6.4 HPF Stage
      7. 7.3.7 Clock Input
      8. 7.3.8 GPIO
    4. 7.4 Device Functional Modes
      1. 7.4.1 Power-Down Mode
      2. 7.4.2 Reset
      3. 7.4.3 Synchronization
        1. 7.4.3.1 Pulse-Sync Mode
        2. 7.4.3.2 Continuous-Sync Mode
      4. 7.4.4 Sample Rate Converter
      5. 7.4.5 Offset and Gain Calibration
        1. 7.4.5.1 OFFSET Register
        2. 7.4.5.2 GAIN Register
        3. 7.4.5.3 Calibration Procedure
    5. 7.5 Programming
      1. 7.5.1 Serial Interface
        1. 7.5.1.1 Chip Select (CS)
        2. 7.5.1.2 Serial Clock (SCLK)
        3. 7.5.1.3 Data Input (DIN)
        4. 7.5.1.4 Data Output (DOUT)
        5. 7.5.1.5 Data Ready (DRDY)
      2. 7.5.2 Conversion Data Format
      3. 7.5.3 Commands
        1. 7.5.3.1  Single Byte Command
        2. 7.5.3.2  WAKEUP: Wake Command
        3. 7.5.3.3  STANDBY: Software Power-Down Command
        4. 7.5.3.4  SYNC: Synchronize Command
        5. 7.5.3.5  RESET: Reset Command
        6. 7.5.3.6  Read Data Direct
        7. 7.5.3.7  RDATA: Read Conversion Data Command
        8. 7.5.3.8  RREG: Read Register Command
        9. 7.5.3.9  WREG: Write Register Command
        10. 7.5.3.10 OFSCAL: Offset Calibration Command
        11. 7.5.3.11 GANCAL: Gain Calibration Command
  9. 8 Register Map
    1. 8.1 Register Descriptions
      1. 8.1.1 ID/SYNC: Device ID, SYNC Register (Address = 00h) [Reset = xxxx0010b]
      2. 8.1.2 CONFIG0: Configuration Register 0 (Address = 01h) [Reset = 92h]
      3. 8.1.3 CONFIG1: Configuration Register 1 (Address = 02h) [Reset = 10h]
      4. 8.1.4 HPF0, HPF1: High-Pass Filter Registers (Address = 03h, 04h) [Reset = 32h, 03h]
      5. 8.1.5 OFFSET0, OFFSET1, OFFSET2: Offset Calibration Registers (Address = 05h, 06h, 07h) [Reset = 00h, 00h, 00h]
      6. 8.1.6 GAIN0, GAIN1, GAIN2: Gain Calibration Registers (Address = 08h, 09h, 0Ah) [Reset = 00h, 00h, 40h]
      7. 8.1.7 GPIO: Digital Input/Output Register (Address = 0Bh) [Reset = 000xx000b]
      8. 8.1.8 SRC0, SRC1: Sample Rate Converter Registers (Address = 0Ch, 0Dh) [Reset = 00h, 80h]
  10. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
      3. 9.2.3 Application Curves
    3. 9.3 Power Supply Recommendations
      1. 9.3.1 Analog Power Supplies
      2. 9.3.2 Digital Power Supply
      3. 9.3.3 Grounds
      4. 9.3.4 Thermal Pad
    4. 9.4 Layout
      1. 9.4.1 Layout Guidelines
      2. 9.4.2 Layout Example
  11. 10Device and Documentation Support
    1. 10.1 接收文档更新通知
    2. 10.2 支持资源
    3. 10.3 Trademarks
    4. 10.4 静电放电警告
    5. 10.5 术语表
  12. 11Revision History
  13. 12Mechanical, Packaging, and Orderable Information

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6.1 Noise Performance

The ADS1288 is a low-power, low-noise, delta-sigma ADC operating on the principle of oversampling. Oversampling averages the high-frequency data of the modulator to produce the final output data. Increasing the oversampling ratio lowers the data rate, the corresponding signal bandwidth, and total noise by averaging more samples from the modulator to yield one conversion result.

The gain of the PGA reduces noise when the noise value is referred to the input. With increased gain, dynamic range performance decreases because the ratio of the input voltage range to the input-referred voltage noise also decreases.

Dynamic range and input noise are equivalent parameters that describe the available resolution of the ADC. Equation 1 derives dynamic range from the input-referred noise data:

Equation 1. GUID-20200813-CA0I-CGML-9LQJ-BVLCJMW5QGSL-low.svg

where:

  • en = Input-referred voltage noise (RMS)
Table 6-1 shows dynamic range and input-referred noise performance, tested with input source resistance (RS) = 0Ω. Noise data are at TA = 25°C and are representative of typical ADC performance. The data are the standard deviation of 4096 consecutive ADC conversion results with the ADC inputs shorted, measured over the 0.413 × fDATA bandwidth. Because of the statistical nature of noise, repeated measurements can yield varying noise performance results.
Table 6-1 Noise Performance (AVDD1 = 3.3V or 5V, RS = 0Ω)
GAIN MODE DYNAMIC RANGE (dB) en, INPUT-REFERRED NOISE (μVRMS)
fDATA (SPS) fDATA (SPS)
125 250 500 1000 2000 125 250 500 1000 2000
1 Buffer 128 125 122 119 116 0.70 0.99 1.4 2.0 2.8
1(1) PGA 128 125 122 119 116 0.70 0.99 1.4 2.0 2.8
2 PGA 127 124 121 118 115 0.39 0.56 0.79 1.1 1.6
4 PGA 126 123 120 117 114 0.23 0.32 0.45 0.63 0.89
8 PGA 123 120 117 114 111 0.16 0.22 0.31 0.44 0.62
16 PGA 118 115 112 109 106 0.14 0.20 0.28 0.39 0.55
32 PGA 112 109 106 103 100 0.14 0.20 0.28 0.39 0.55
64 PGA 106 103 100 97 94 0.14 0.20 0.28 0.39 0.55
(1) PGA gain = 1 dynamic range performance specified at AVDD1 = 5V.