JAJSGE8B March   2016  – October 2018 ADS1282-SP

PRODUCTION DATA.  

  1. 1 特長
  2. 2 アプリケーション
  3. 3 概要
    1.     Device Images
      1.      概略回路図
  4. 4 改訂履歴
  5. 5 概要（続き）
  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デバイスおよびドキュメントのサポート
    1. 12.1 デバイス・サポート
      1. 12.1.1 HPF伝達関数
    2. 12.2 ドキュメントの更新通知を受け取る方法
    3. 12.3 コミュニティ・リソース
    4. 12.4 商標
    5. 12.5 静電気放電に関する注意事項
    6. 12.6 Glossary
  13. 13メカニカル、パッケージ、および注文情報

パッケージ・オプション

メカニカル・データ（パッケージ｜ピン）
サーマルパッド・メカニカル・データ
発注情報

8.3.6 PGA (Programmable Gain Amplifier)

The PGA of the ADS1282-SP is a low-noise, continuous-time, differential-in/differential-out CMOS amplifier. The gain is programmable from 1 to 64, set by register bits, PGA[2:0]. The PGA differentially drives the modulator through 300-Ω internal resistors. A COG capacitor (10 nF typical) must be connected to CAPP and CAPN to filter modulator sampling glitches. The external capacitor also serves as an anti-alias filter. The corner frequency is given in Equation 3:

Equation 3. ADS1282-SP q_fp_bas418.gif

Referring to Figure 29, amplifiers A1 and A2 are chopped to remove the offset, offset drift, and the 1/f noise. Chopping moves the effects to ƒCLK/128 (8 kHz), which is safely out of the passband. Chopping can be disabled by setting the CHOP register bit = 0. With chopping disabled, the impedance of the PGA increases substantially (>> 1 GΩ). As shown in Figure 30, chopping maintains flat noise density; if chopping is disabled, however, it results in a rising 1/f noise profile.

The PGA has programmable gains from 1 to 64. Table 3 shows the register bit setting for the PGA and resulting full-scale differential range.

The specified output operating range of the PGA is shown in Equation 4:

Equation 4. AVSS + 0.4 V < (CAPN or CAPP) < AVDD – 0.4 V

PGA output levels (signal plus common-mode) should be maintained within these limits for best operation.

Table 3. PGA Gain Settings

PGA[2:0] GAIN DIFFERENTIAL INPUT RANGE (V)(1)
000 1 ±2.5
001 2 ±1.25
010 4 ±0.625
011 8 ±0.312
100 16 ±0.156
101 32 ±0.078
110 64 ±0.039
(1) VREF = VREFP – VREFN = 5 V
ADS1282-SP ai_pga_fbd_bas418.gifFigure 29. PGA Block Diagram
ADS1282-SP ai_pga_noise_bas418.gifFigure 30. PGA Noise