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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7.4.4 Sample Rate Converter

The sample rate converter (SRC) compensates clock frequency error by resampling the modulator data at a new rate set by a compensation factor written to the SRC registers. The compensation range is ±244ppm with 7.45ppb (1 / 227) resolution.

Clock frequency error is compensated by writing a value to the SCR0 and SRC1 registers. The register value is in two's-complement format for positive and negative error compensation. Positive register data values decrease the data rate frequency (increases the period). The compensated data rate frequency is observed by the frequency of the DRDY signal.

Table 7-7 shows example values of SRC compensation. 8000h disables the sample rate converter. 0000h passes the data through with no compensation but adds an 8 / fCLK delay to the existing time delay of SYNC input to the DRDY pulses.

Table 7-7 Example SRC Compensation Values
SRC[15:0] VALUECOMPENSATION FACTOR
7FFFh(1 – 32,767 / 227) × fDATA
0001h(1 – 1 / 227) × fDATA
0000h1 × fDATA
7FFFh(1 + 1 / 227) × fDATA
8001h(1 + 32,767 / 227) × fDATA
8000h1 × fDATA (SRC disabled)

Resynchronize the ADC after the sample rate converter is enabled or disabled.

Because the SRC is a digital function, operation is deterministic without error. When the target compensation value is determined, the value can be immediately written to the ADC, or incrementally written up to the determined value to reduce the effect of step changes in the output frequency. Because two bytes are used for the SRC registers, use the multibyte command operation to write to the SRC registers and complete the write operation 256 CLK cycles before the DRDY falling edge. This procedure simultaneously loads the high and low bytes for compensation. See Figure 5-7 for details.