SBASA61A December   2020  – June 2021 PCM1820 , PCM1821

PRODUCTION DATA  

  1. Features
  2. Applications
  3. Description
  4. Revision History
  5. Device Comparison Table
  6. Pin Configuration and Functions
  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: TDM, I2S or LJ Interface
    7. 7.7 Switching Characteristics: TDM, I2S or LJ Interface
    8. 7.8 Typical Characteristics
  8. Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Hardware Control
      2. 8.3.2 Audio Serial Interfaces
        1. 8.3.2.1 Time Division Multiplexed Audio (TDM) Interface
        2. 8.3.2.2 Inter IC Sound (I2S) Interface
      3. 8.3.3 Phase-Locked Loop (PLL) and Clock Generation
      4. 8.3.4 Input Channel Configurations
      5. 8.3.5 Reference Voltage
      6. 8.3.6 Signal-Chain Processing
        1. 8.3.6.1 Digital High-Pass Filter
        2. 8.3.6.2 Configurable Digital Decimation Filters
          1. 8.3.6.2.1 Linear Phase Filters
            1. 8.3.6.2.1.1 Sampling Rate: 8 kHz or 7.35 kHz
            2. 8.3.6.2.1.2 Sampling Rate: 16 kHz or 14.7 kHz
            3. 8.3.6.2.1.3 Sampling Rate: 24 kHz or 22.05 kHz
            4. 8.3.6.2.1.4 Sampling Rate: 32 kHz or 29.4 kHz
            5. 8.3.6.2.1.5 Sampling Rate: 48 kHz or 44.1 kHz
            6. 8.3.6.2.1.6 Sampling Rate: 96 kHz or 88.2 kHz
            7. 8.3.6.2.1.7 Sampling Rate: 192 kHz or 176.4 kHz
          2. 8.3.6.2.2 Low-Latency Filters
            1. 8.3.6.2.2.1 Sampling Rate: 16 kHz or 14.7 kHz
            2. 8.3.6.2.2.2 Sampling Rate: 24 kHz or 22.05 kHz
            3. 8.3.6.2.2.3 Sampling Rate: 32 kHz or 29.4 kHz
            4. 8.3.6.2.2.4 Sampling Rate: 48 kHz or 44.1 kHz
            5. 8.3.6.2.2.5 Sampling Rate: 96 kHz or 88.2 kHz
      7. 8.3.7 Dynamic Range Enhancer (DRE)
    4. 8.4 Device Functional Modes
      1. 8.4.1 Active Mode
  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
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Receiving Notification of Documentation Updates
    2. 12.2 Support Resources
    3. 12.3 Trademarks
    4. 12.4 Electrostatic Discharge Caution
    5. 12.5 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Input Channel Configurations

The device consists of two pairs of analog input pins (INxP and INxM) as differential inputs for the recording channel. The device supports simultaneous recording of up to two channels using the high-performance stereo ADC. The input source for the analog pins can be from electret condenser analog microphones, micro electrical-mechanical system (MEMS) analog microphones, or line-in (auxiliary) inputs from the system board.

The voice or audio signal inputs must be capacitively coupled (AC-coupled) to the device and, for best distortion performance, use the low-voltage coefficient capacitors for AC coupling. The typical input impedance for the PCM1820 is 2.5 kΩ for the INxP or INxM pins and 10 kΩ for the PCM1821. The value of the coupling capacitor in AC-coupled mode must be chosen so that the high-pass filter formed by the coupling capacitor and the input impedance do not affect the signal content. Before proper recording can begin, this coupling capacitor must be charged up to the common-mode voltage at power-up. To enable quick charging, the device has a quick charge scheme to speed up the charging of the coupling capacitor at power-up. The default value of the quick-charge timing is set for a coupling capacitor up to 1 µF.