ZHCSIZ6C October   2018  – June 2019 ADS125H02

PRODUCTION DATA.  

  1. 1 特性
  2. 2 应用
  3. 3 说明
    1.     功能方框图
  4. 4 修订历史记录
  5. 5 Device Comparison Table
  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 Switching Characteristics
    8. 7.8 Typical Characteristics
  8. 8 Parameter Measurement Information
    1. 8.1 Noise Performance
  9. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 Input Range
      2. 9.3.2 Analog Inputs
        1. 9.3.2.1 ESD Diodes
        2. 9.3.2.2 Input Multiplexer
          1. 9.3.2.2.1 Analog Inputs (AIN0, AIN1, AINCOM)
          2. 9.3.2.2.2 High-Voltage Power Supply Readback
          3. 9.3.2.2.3 Internal VCOM Connection (Default)
          4. 9.3.2.2.4 Temperature Sensor
      3. 9.3.3 Programmable Gain Amplifier (PGA)
        1. 9.3.3.1 PGA Operating Range
        2. 9.3.3.2 PGA Monitor
      4. 9.3.4 Reference Voltage
        1. 9.3.4.1 Internal Reference
        2. 9.3.4.2 External Reference
        3. 9.3.4.3 AVDD Power-Supply Reference
        4. 9.3.4.4 Reference Monitor
      5. 9.3.5 Current Sources (IDAC1 and IDAC2)
      6. 9.3.6 General-Purpose Inputs and Outputs (GPIOs)
      7. 9.3.7 ADC Modulator
      8. 9.3.8 Digital Filter
        1. 9.3.8.1 Sinc Filter Mode
          1. 9.3.8.1.1 Sinc Filter Frequency Response
        2. 9.3.8.2 FIR Filter
        3. 9.3.8.3 50-Hz and 60-Hz Normal Mode Rejection
    4. 9.4 Device Functional Modes
      1. 9.4.1 Conversion Control
        1. 9.4.1.1 Continuous-Conversion Mode
        2. 9.4.1.2 Pulse-Conversion Mode
        3. 9.4.1.3 Conversion Latency
        4. 9.4.1.4 Start-Conversion Delay
      2. 9.4.2 Auto-Zero Mode
      3. 9.4.3 Clock Mode
      4. 9.4.4 Reset
        1. 9.4.4.1 Power-On Reset
        2. 9.4.4.2 Reset by Pin
        3. 9.4.4.3 Reset by Command
      5. 9.4.5 Calibration
        1. 9.4.5.1 Offset and Full-Scale Calibration
          1. 9.4.5.1.1 Offset Calibration Registers
          2. 9.4.5.1.2 Full-Scale Calibration Registers
        2. 9.4.5.2 Offset Calibration (OFSCAL)
        3. 9.4.5.3 Full-Scale Calibration (GANCAL)
        4. 9.4.5.4 Calibration Command Procedure
        5. 9.4.5.5 User Calibration Procedure
    5. 9.5 Programming
      1. 9.5.1 Serial Interface
        1. 9.5.1.1 Chip-Select Pins (CS1 and CS2)
        2. 9.5.1.2 Serial Clock (SCLK)
        3. 9.5.1.3 Data Input (DIN)
        4. 9.5.1.4 Data Output/Data Ready (DOUT/DRDY)
      2. 9.5.2 Data Ready (DRDY)
        1. 9.5.2.1 DRDY in Continuous-Conversion Mode
        2. 9.5.2.2 DRDY in Pulse-Conversion Mode
        3. 9.5.2.3 Data Ready by Software Polling
      3. 9.5.3 Conversion Data
        1. 9.5.3.1 Status Byte (STATUS0)
        2. 9.5.3.2 Conversion Data Format
      4. 9.5.4 Cyclic Redundancy Check (CRC)
      5. 9.5.5 Commands
        1. 9.5.5.1  General Command Format
        2. 9.5.5.2  NOP Command
        3. 9.5.5.3  RESET Command
        4. 9.5.5.4  START Command
        5. 9.5.5.5  STOP Command
        6. 9.5.5.6  RDATA Command
        7. 9.5.5.7  OFSCAL Command
        8. 9.5.5.8  GANCAL Command
        9. 9.5.5.9  RREG Command
        10. 9.5.5.10 WREG Command
        11. 9.5.5.11 LOCK Command
        12. 9.5.5.12 UNLOCK Command
    6. 9.6 Register Map
      1. 9.6.1  Device Identification (ID) Register (address = 00h) [reset = 6xh]
        1. Table 30. ID Register Field Descriptions
      2. 9.6.2  Main Status (STATUS0) Register (address = 01h) [reset = 01h]
        1. Table 31. STATUS0 Register Field Descriptions
      3. 9.6.3  Mode 0 (MODE0) Register (address = 02h) [reset = 24h]
        1. Table 32. MODE0 Register Field Descriptions
      4. 9.6.4  Mode 1 (MODE1) Register (address = 03h) [reset = 01h]
        1. Table 33. MODE1 Register Field Descriptions
      5. 9.6.5  Mode 2 (MODE2) Register (address = 04h) [reset = 00h]
        1. Table 34. MODE2 Register Field Descriptions
      6. 9.6.6  Mode 3 (MODE3) Register (address = 05h) [reset = 00h]
        1. Table 35. MODE3 Register Field Descriptions
      7. 9.6.7  Reference Configuration (REF) Register (address = 06h) [reset = 05h]
        1. Table 36. REF Register Field Descriptions
      8. 9.6.8  Offset Calibration (OFCALx) Registers (address = 07h, 08h, 09h) [reset = 00h, 00h, 00h]
        1. Table 37. OFCAL0, OFCAL1, OFCAL2 Registers Field Description
      9. 9.6.9  Full-Scale Calibration (FSCALx) Registers (address = 0Ah, 0Bh, 0Ch) [reset = 00h, 00h, 40h]
        1. Table 38. FSCAL0, FSCAL1, FSCAL2 Registers Field Description
      10. 9.6.10 Current Source Multiplexer (I_MUX) Register (address = 0Dh) [reset = FFh]
        1. Table 39. I_MUX Register Field Descriptions
      11. 9.6.11 Current Source Magnitude (I_MAG) Register (address = 0Eh) [reset = 00h]
        1. Table 40. I_MAG Register Field Descriptions
      12. 9.6.12 Reserved (RESERVED) Register (address = 0Fh) [reset = 00h]
        1. Table 41. RESERVED Register Field Descriptions
      13. 9.6.13 MODE4 (MODE4) Register (address = 10h) [reset = 50h]
        1. Table 42. MODE4 Register Field Descriptions
      14. 9.6.14 PGA Alarm (STATUS1) Register (address = 11h) [reset = xxh]
        1. Table 43. STATUS1 Register Field Descriptions
      15. 9.6.15 Status 2 (STATUS2) Register (address = 12h) [reset = 0xh]
        1. Table 44. STATUS2 Register Field Descriptions
  10. 10Application and Implementation
    1. 10.1 Application Information
      1. 10.1.1 Input Range
      2. 10.1.2 Input Overload
        1. 10.1.2.1 Input Signal Rate of Change (dV/dt)
      3. 10.1.3 Unused Inputs and Outputs
    2. 10.2 Typical Applications
      1. 10.2.1 ±10-V Analog Input Module
        1. 10.2.1.1 Design Requirements
        2. 10.2.1.2 Detailed Design Procedure
        3. 10.2.1.3 Application Curves
      2. 10.2.2 Thermocouple Input With High Common-Mode Voltage
    3. 10.3 Initialization Setup
  11. 11Power Supply Recommendations
    1. 11.1 Power-Supply Decoupling
    2. 11.2 Analog Power-Supply Clamp
    3. 11.3 Power-Supply Sequencing
    4. 11.4 5-V to ±15-V DC-DC Converter
  12. 12Layout
    1. 12.1 Layout Guidelines
    2. 12.2 Layout Example
  13. 13器件和文档支持
    1. 13.1 文档支持
      1. 13.1.1 相关文档
    2. 13.2 接收文档更新通知
    3. 13.3 社区资源
    4. 13.4 商标
    5. 13.5 静电放电警告
    6. 13.6 Glossary
  14. 14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

9.3.8.1.1 Sinc Filter Frequency Response

As shown in Figure 66 and Figure 67, the first-stage sinc5 filter has frequency response nulls occurring at N × fDATA (where N = 1, 2, 3, and so on). At the null frequencies, the filter has zero gain.

ADS125H02 D201_SBAS760.gifFigure 66. Sinc Frequency Response (40000 SPS)
ADS125H02 D002_sbas661.gifFigure 67. Sinc Frequency Response (14400 SPS)

The second stage superimposes additional nulls to the nulls produced by the first stage. The first of the superimposed nulls occurs at the output data rate with additional nulls at multiples of the output data rate.

Figure 68 shows the frequency response of the combined filter stages at 2400 SPS. This data rate has five equally-spaced nulls residing between the larger nulls at 14400-Hz multiples that are produced by the first stage. This frequency response is similar to that of data rates 2.5 SPS to 7200 SPS. Figure 69 shows the frequency response nulls at 10 SPS.

ADS125H02 D003_sbas661.gifFigure 68. Sinc Frequency Response (2400 SPS)
ADS125H02 D004_sbas661.gifFigure 69. Sinc Frequency Response (10 SPS)

Figure 70 and Figure 71 show the frequency response of data rates 50 SPS and 60 SPS, respectively. The frequency response is plotted to the 50-Hz 12th harmonic (10th harmonic for 60 Hz). The 50-Hz or 60-Hz fundamental and harmonic noise of the signal are reduced by increasing the filter order of the second stage.

ADS125H02 D005_sbas661.gifFigure 70. Sinc Frequency Response (50 SPS)
ADS125H02 D006_sbas661.gifFigure 71. Sinc Frequency Response (60 SPS)

Figure 72 and Figure 73 plot the detailed frequency response of the 50-SPS and 60-SPS data rates and show various orders of the sinc filter. The high-order sinc filter increases the frequency width of the null, which improves line cycle rejection. Improved 50-Hz or 60-Hz rejection occurs using the sinc3 or sinc4 order filter.

ADS125H02 D009_sbas661.gifFigure 72. Sinc Frequency Response, Detailed (50 SPS)
ADS125H02 D010_sbas661.gifFigure 73. Sinc Frequency Response, Detailed (60 SPS)

The sinc filter has an overall low-pass response that rolls off high-frequency components of the signal. The filter bandwidth depends on the output data rate and the order of the output data rate. The overall system bandwidth is the combined responses of the digital filter, the PGA antialias filter, and external signal filters. Table 5 lists the –3-dB bandwidth of the sinc filter.

Table 5. Sinc Filter Bandwidth

-3-dB BANDWIDTH (Hz)
DATA RATE (SPS) SINC1 SINC2 SINC3 SINC4 SINC5
2.5 1.10 0.80 0.65 0.58 —
5 2.23 1.60 1.33 1.15 —
10 4.43 3.20 2.62 2.28 —
16.6 7.38 5.33 4.37 3.80 —
20 8.85 6.38 5.25 4.63 —
50 22.1 16.0 13.1 11.4 —
60 26.6 19.1 15.7 13.7 —
100 44.3 31.9 26.2 22.8 —
400 177 128 105 91.0 —
1200 525 381 314 273 —
2400 1015 751 623 544 —
4800 1798 1421 1214 1077 —
7200 2310 1972 1750 1590 —
14400 — — — — 2940
19200 — — — — 3920
25600 — — — — 5227
40000 — — — — 8167