SBASA64A December   2020  – June 2021 PCMD3140

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 6 Specifications
    1. 6.1  Absolute Maximum Ratings
    2. 6.2  ESD Ratings
    3. 6.3  Recommended Operating Conditions
    4. 6.4  Thermal Information
    5. 6.5  Electrical Characteristics
    6. 6.6  Timing Requirements: I2C Interface
    7. 6.7  Switching Characteristics: I2C Interface
    8. 6.8  Timing Requirements: TDM, I2S or LJ Interface
    9. 6.9  Switching Characteristics: TDM, I2S or LJ Interface
    10. 6.10 Timing Requirements: PDM Digital Microphone Interface
    11. 6.11 Switching Characteristics: PDM Digial Microphone Interface
    12. 6.12 Timing Diagrams
    13. 6.13 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Serial Interfaces
        1. 7.3.1.1 Control Serial Interfaces
        2. 7.3.1.2 Audio Serial Interfaces
          1. 7.3.1.2.1 Time Division Multiplexed Audio (TDM) Interface
          2. 7.3.1.2.2 Inter IC Sound (I2S) Interface
          3. 7.3.1.2.3 Left-Justified (LJ) Interface
        3. 7.3.1.3 Using Multiple Devices With Shared Buses
      2. 7.3.2 Phase-Locked Loop (PLL) and Clock Generation
      3. 7.3.3 Reference Voltage
      4. 7.3.4 Microphone Bias
      5. 7.3.5 Digital PDM Microphone Record Channel
      6. 7.3.6 Signal-Chain Processing
        1. 7.3.6.1 Programmable Digital Volume Control
        2. 7.3.6.2 Programmable Channel Gain Calibration
        3. 7.3.6.3 Programmable Channel Phase Calibration
        4. 7.3.6.4 Programmable Digital High-Pass Filter
        5. 7.3.6.5 Programmable Digital Biquad Filters
        6. 7.3.6.6 Programmable Channel Summer and Digital Mixer
        7. 7.3.6.7 Configurable Digital Decimation Filters
          1. 7.3.6.7.1 Linear Phase Filters
            1. 7.3.6.7.1.1 Sampling Rate: 7.35 kHz to 8 kHz
            2. 7.3.6.7.1.2 Sampling Rate: 14.7 kHz to 16 kHz
            3. 7.3.6.7.1.3 Sampling Rate: 22.05 kHz to 24 kHz
            4. 7.3.6.7.1.4 Sampling Rate: 29.4 kHz to 32 kHz
            5. 7.3.6.7.1.5 Sampling Rate: 44.1 kHz to 48 kHz
            6. 7.3.6.7.1.6 Sampling Rate: 88.2 kHz to 96 kHz
            7. 7.3.6.7.1.7 Sampling Rate: 176.4 kHz to 192 kHz
            8. 7.3.6.7.1.8 Sampling Rate: 352.8 kHz to 384 kHz
            9. 7.3.6.7.1.9 Sampling Rate: 705.6 kHz to 768 kHz
          2. 7.3.6.7.2 Low-Latency Filters
            1. 7.3.6.7.2.1 Sampling Rate: 14.7 kHz to 16 kHz
            2. 7.3.6.7.2.2 Sampling Rate: 22.05 kHz to 24 kHz
            3. 7.3.6.7.2.3 Sampling Rate: 29.4 kHz to 32 kHz
            4. 7.3.6.7.2.4 Sampling Rate: 44.1 kHz to 48 kHz
            5. 7.3.6.7.2.5 Sampling Rate: 88.2 kHz to 96 kHz
            6. 7.3.6.7.2.6 Sampling Rate: 176.4 kHz to 192 kHz
          3. 7.3.6.7.3 Ultra-Low-Latency Filters
            1. 7.3.6.7.3.1 Sampling Rate: 14.7 kHz to 16 kHz
            2. 7.3.6.7.3.2 Sampling Rate: 22.05 kHz to 24 kHz
            3. 7.3.6.7.3.3 Sampling Rate: 29.4 kHz to 32 kHz
            4. 7.3.6.7.3.4 Sampling Rate: 44.1 kHz to 48 kHz
            5. 7.3.6.7.3.5 Sampling Rate: 88.2 kHz to 96 kHz
            6. 7.3.6.7.3.6 Sampling Rate: 176.4 kHz to 192 kHz
            7. 7.3.6.7.3.7 Sampling Rate: 352.8 kHz to 384 kHz
      7. 7.3.7 Voice Activity Detection (VAD)
      8. 7.3.8 Interrupts, Status, and Digital I/O Pin Multiplexing
    4. 7.4 Device Functional Modes
      1. 7.4.1 Sleep Mode or Software Shutdown
      2. 7.4.2 Active Mode
      3. 7.4.3 Software Reset
    5. 7.5 Programming
      1. 7.5.1 Control Serial Interfaces
        1. 7.5.1.1 I2C Control Interface
          1. 7.5.1.1.1 General I2C Operation
          2. 7.5.1.1.2 I2C Single-Byte and Multiple-Byte Transfers
            1. 7.5.1.1.2.1 I2C Single-Byte Write
            2. 7.5.1.1.2.2 I2C Multiple-Byte Write
            3. 7.5.1.1.2.3 I2C Single-Byte Read
            4. 7.5.1.1.2.4 I2C Multiple-Byte Read
    6. 7.6 Register Maps
      1. 7.6.1 Page 0 Registers
      2. 7.6.2 Page 1 Registers
      3. 7.6.3 Programmable Coefficient Registers
        1. 7.6.3.1 Programmable Coefficient Registers: Page 2
        2. 7.6.3.2 Programmable Coefficient Registers: Page 3
        3. 7.6.3.3 Programmable Coefficient Registers: Page 4
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Four-Channel Digital PDM Microphone Recording
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1 Example Device Register Configuration Script for EVM Setup
        3. 8.2.1.3 Application Curves
    3. 8.3 What to Do and What Not to Do
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Support Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

7.3.6.6 Programmable Channel Summer and Digital Mixer

For applications that require an even higher SNR than that supported for each channel, the device digital summing mode can be used. In this mode, the digital record data are summed up across the channel with an equal weightage factor, which helps in reducing the effective record noise. Table 7-17 lists the configuration settings available for channel summing mode.

Table 7-17 Channel Summing Mode Programmable Settings
P0_R107_D[3:2] : CH_SUM[2:0] CHANNEL SUMMING MODE FOR INPUT CHANNELS SNR AND DYNAMIC RANGE BOOST
00 (default) Channel summing mode is disabled Not applicable
01 Output channel 1 = (input channel 1 + input channel 2) / 2 3-dB boost in SNR and dynamic range
Output channel 2 = (input channel 1 + input channel 2) / 2
Output channel 3 = (input channel 3 + input channel 4) / 2 3-dB boost in SNR and dynamic range
Output channel 4 = (input channel 3 + input channel 4) / 2
10 Reserved (do not use this setting) Not applicable
11 Reserved (do not use this setting) Not applicable

The device additionally supports a fully programmable mixer feature that can mix the various input channels with their custom programmable scale factor to generate the final output channels. The programmable mixer feature is available only if CH_SUM[2:0] is set to 2'b00. The mixer function is supported for all 4 input channels. Figure 7-18 shows a block diagram that describes the mixer 1 operation to generate output channel 1. The programmable coefficients for the mixer operation are located in the Section 7.6.3.3 section. All mixer coefficients are 32-bit, two’s complement numbers using a 1.31 number format. The value of 0x7FFFFFFF is equivalent to +1 (0-dB gain), the value 0x00000000 is equivalent to mute (zero data), and any values in between set the mixer attenuation computed using Equation 3. If the MSB is set to '1' then the attenuation remains the same but the signal phase is inverted.

Equation 3. hex2dec (value) / 231
GUID-014EBA2A-1F30-4F74-9A49-A68A00CB9BB2-low.gifFigure 7-18 Programmable Digital Mixer Block Diagram

A similar mixer operation is performed by mixer 2, mixer 3, and mixer 4 to generate output channel 2, channel 3, and channel 4, respectively.