ZHCSES1B March   2016  – October 2018 ADS1282-SP

PRODUCTION DATA.  

  1. 1 特性
  2. 2 应用
  3. 3 说明
    1.     Device Images
      1.      简化原理图
  4. 4 修订历史记录
  5. 5 （说明 （续））
  6. 6 Pin Configuration and Functions
    1.     Pin Functions
  7. 7 Specifications
    1. 7.1  Absolute Maximum Ratings
    2. 7.2  ESD Ratings
    3. 7.3  Recommended Operating Conditions
    4. 7.4  Thermal Information
    5. 7.5  Electrical Characteristics
    6. 7.6  Timing Requirements
    7. 7.7  Pulse-Sync Timing Requirements
    8. 7.8  Reset Timing Requirements
    9. 7.9  Read Data Timing Requirements
    10. 7.10 Switching Characteristics
    11. 7.11 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1  Noise Performance
      2. 8.3.2  Input-Referred Noise
      3. 8.3.3  Idle Tones
      4. 8.3.4  Operating Mode
      5. 8.3.5  Analog Inputs and Multiplexer
      6. 8.3.6  PGA (Programmable Gain Amplifier)
      7. 8.3.7  ADC
      8. 8.3.8  Modulator
      9. 8.3.9  Modulator Over-Range
      10. 8.3.10 Modulator Input Impedance
      11. 8.3.11 Modulator Over-Range Detection (MFLAG)
      12. 8.3.12 Voltage Reference Inputs (VREFP, VREFN)
      13. 8.3.13 Digital Filter
        1. 8.3.13.1 Sinc Filter Stage (Sinx/X)
        2. 8.3.13.2 FIR Stage
        3. 8.3.13.3 Group Delay and Step Response
          1. 8.3.13.3.1 Linear Phase Response
          2. 8.3.13.3.2 Minimum Phase Response
        4. 8.3.13.4 HPF Stage
      14. 8.3.14 Master Clock Input (CLK)
      15. 8.3.15 Synchronization (SYNC Pin and Sync Command)
      16. 8.3.16 Pulse-Sync Mode
      17. 8.3.17 Continuous-Sync Mode
      18. 8.3.18 Reset (RESET Pin and Reset Command)
      19. 8.3.19 Power-Down (PWDN Pin and Standby Command)
      20. 8.3.20 Power-On Sequence
      21. 8.3.21 Serial Interface
        1. 8.3.21.1 Serial Clock (SCLK)
        2. 8.3.21.2 Data Input (DIN)
        3. 8.3.21.3 Data Output (DOUT)
        4. 8.3.21.4 Data Ready (DRDY)
      22. 8.3.22 Data Format
      23. 8.3.23 Reading Data
        1. 8.3.23.1 Read Data Continuous
        2. 8.3.23.2 Read Data by Command
      24. 8.3.24 One-Shot Operation
    4. 8.4 Device Functional Modes
      1. 8.4.1 Modulator Output Mode
    5. 8.5 Programming
      1. 8.5.1 Commands
        1. 8.5.1.1  WAKEUP: Wake-Up from Standby Mode
        2. 8.5.1.2  STANDBY: Standby Mode
        3. 8.5.1.3  SYNC: Synchronize the A/D Conversion
        4. 8.5.1.4  RESET: Reset the Device
        5. 8.5.1.5  RDATAC: Read Data Continuous
        6. 8.5.1.6  SDATAC: Stop Read Data Continuous
        7. 8.5.1.7  RDATA: Read Data By Command
        8. 8.5.1.8  RREG: Read Register Data
        9. 8.5.1.9  WREG: Write to Register
        10. 8.5.1.10 OFSCAL: Offset Calibration
        11. 8.5.1.11 GANCAL: Gain Calibration
      2. 8.5.2 Calibration Commands
        1. 8.5.2.1 OFSCAL Command
        2. 8.5.2.2 GANCAL Command
      3. 8.5.3 User Calibration
      4. 8.5.4 Configuration Guide
    6. 8.6 Register Maps
      1. 8.6.1 ADS1282-SP Register Map Information
      2. 8.6.2 ID Register
        1. Table 13. ID Register Field Descriptions
      3. 8.6.3 Configuration Registers
        1. 8.6.3.1 Configuration Register 0
          1. Table 14. Configuration Register 0 Field Descriptions
        2. 8.6.3.2 Configuration Register 1
          1. Table 15. Configuration Register 1 Field Descriptions
      4. 8.6.4 HPF1 and HPF0
        1. 8.6.4.1 High-Pass Filter Corner Frequency, Low Byte
        2. 8.6.4.2 High-Pass Filter Corner Frequency, High Byte
      5. 8.6.5 OFC2, OFC1, OFC0
        1. 8.6.5.1 Offset Calibration, Low Byte
        2. 8.6.5.2 Offset Calibration, Mid Byte
        3. 8.6.5.3 Offset Calibration, High Byte
      6. 8.6.6 FSC2, FSC1, FSC0
        1. 8.6.6.1 Full-Scale Calibration, Low Byte
        2. 8.6.6.2 Full-Scale Calibration, Mid Byte
        3. 8.6.6.3 Full-Scale Calibration, High Byte
      7. 8.6.7 Offset and Full-Scale Calibration Registers
        1. 8.6.7.1 OFC[2:0] Registers
        2. 8.6.7.2 FSC[2:0] Registers
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Thermocouple Temperature Sensing Application
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
      2. 9.2.2 Digital Connection to a Field Programmable Gate Array (FPGA) Device Typical Application
        1. 9.2.2.1 Design Requirements
        2. 9.2.2.2 Detailed Design Procedure
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12器件和文档支持
    1. 12.1 器件支持
      1. 12.1.1 HPF 传递函数
    2. 12.2 接收文档更新通知
    3. 12.3 社区资源
    4. 12.4 商标
    5. 12.5 静电放电警告
    6. 12.6 术语表
  13. 13机械、封装和可订购信息

封装选项

机械数据 (封装 | 引脚)
散热焊盘机械数据 (封装 | 引脚)
订购信息

8.3.5 Analog Inputs and Multiplexer

Figure 26 shows a diagram of the input multiplexer.

ESD diodes protect the multiplexer inputs. If either input is taken less than AVSS – 0.3 V or greater than AVDD + 0.3 V, the ESD protection diodes may turn on. If these conditions are possible, external Schottky clamp diodes and/or series resistors may be required to limit the input current to safe values (see the Absolute Maximum Ratings).

Also, overdriving one unused input may affect the conversions of the other input. If overdriven inputs are possible, TI recommends clamping the signal with external Schottky diodes.

ADS1282-SP ai_ana_in_mux_bas418.gifFigure 26. Analog Inputs and Multiplexer

The specified input operating range of the PGA is shown in Equation 2:

Equation 2. AVSS + 0.7 V < (AINN or AINP) < AVDD – 1.25 V

Absolute input levels (input signal level and common-mode level) should be maintained within these limits for best operation.

The multiplexer connects one of the two external differential inputs to the preamplifier inputs, in addition to internal connections for various self-test modes. Table 2 summarizes the multiplexer configurations for Figure 26.

Table 2. Multiplexer Modes

MUX[2:0] SWITCHES DESCRIPTION
000 S1, S5 AINP1 and AINN1 connected to preamplifier
001 S2, S6 AINP2 and AINN2 connected to preamplifier
010 S3, S4 Preamplifier inputs shorted together through 400Ω internal resistors
011 S1, S5, S2, S6 AINP1, AINN1 and AINP2, AINN2 connected together and to the preamplifier
100 S6, S7 External short, preamplifier inputs shorted to AINN2 (common-mode test)

The typical on-resistance (RON) of the multiplexer switch is 30 Ω. When the multiplexer is used to drive an external load on one input by a signal generator on the other input, on-resistance and on-resistance amplitude dependency can lead to measurement errors. Figure 27 shows THD versus load resistance and amplitude. THD improves with high-impedance loads and with lower amplitude drive signals. The data are measured with the circuit from Figure 28 with MUX[2:0] = 011.

ADS1282-SP ai_thd-ch_load_bas418.gifFigure 27. THD vs External Load and Signal Magnitude (PGA) (See Figure 28)
ADS1282-SP ai_input1-2_bas418.gifFigure 28. Driving an External Load Through the MUX