SBASAU2 May   2024 PCM1841-Q1

ADVANCE INFORMATION  

  1.   1
  2. 1Features
  3. 2Applications
  4. 3Description
  5. 4Pin Configuration and Functions
  6. 5Specifications
    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: TDM, I2S or LJ Interface
    7. 5.7 Switching Characteristics: TDM, I2S or LJ Interface
    8. 5.8 Timing Diagram
    9. 5.9 Typical Characteristics
  7. 6Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1 Hardware Control
      2. 6.3.2 Audio Serial Interfaces
        1. 6.3.2.1 Time Division Multiplexed Audio (TDM) Interface
        2. 6.3.2.2 Inter IC Sound (I2S) Interface
        3. 6.3.2.3 Left-Justified (LJ) Interface
      3. 6.3.3 Phase-Locked Loop (PLL) and Clock Generation
      4. 6.3.4 Input Channel Configurations
      5. 6.3.5 Reference Voltage
      6. 6.3.6 Microphone Bias
      7. 6.3.7 Signal-Chain Processing
        1. 6.3.7.1 Digital High-Pass Filter
        2. 6.3.7.2 Configurable Digital Decimation Filters
          1. 6.3.7.2.1 Linear Phase Filters
            1. 6.3.7.2.1.1 Sampling Rate: 8kHz or 7.35kHz
            2. 6.3.7.2.1.2 Sampling Rate: 16kHz or 14.7kHz
            3. 6.3.7.2.1.3 Sampling Rate: 24kHz or 22.05kHz
            4. 6.3.7.2.1.4 Sampling Rate: 32kHz or 29.4kHz
            5. 6.3.7.2.1.5 Sampling Rate: 48kHz or 44.1kHz
            6. 6.3.7.2.1.6 Sampling Rate: 96kHz or 88.2kHz
            7. 6.3.7.2.1.7 Sampling Rate: 192kHz or 176.4kHz
          2. 6.3.7.2.2 Low-Latency Filters
            1. 6.3.7.2.2.1 Sampling Rate: 16kHz or 14.7kHz
            2. 6.3.7.2.2.2 Sampling Rate: 24kHz or 22.05kHz
            3. 6.3.7.2.2.3 Sampling Rate: 32kHz or 29.4kHz
            4. 6.3.7.2.2.4 Sampling Rate: 48kHz or 44.1kHz
            5. 6.3.7.2.2.5 Sampling Rate: 96kHz or 88.2kHz
      8. 6.3.8 Dynamic Range Enhancer (DRE)
    4. 6.4 Device Functional Modes
      1. 6.4.1 Hardware Shutdown
      2. 6.4.2 Active Mode
  8. 7Application and Implementation
    1. 7.1 Application Information
    2. 7.2 Typical Application
      1. 7.2.1 Design Requirements
      2. 7.2.2 Detailed Design Procedure
      3. 7.2.3 Application Curves
    3. 7.3 Power Supply Recommendations
    4. 7.4 Layout
      1. 7.4.1 Layout Guidelines
      2. 7.4.2 Layout Example
  9. 8Device and Documentation Support
    1. 8.1 Receiving Notification of Documentation Updates
    2. 8.2 Support Resources
    3. 8.3 Trademarks
    4. 8.4 Electrostatic Discharge Caution
    5. 8.5 Glossary
  10. 9Revision History
  11.   Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

6.3.8 Dynamic Range Enhancer (DRE)

The device integrates an ultra-low noise, front-end DRE gain amplifier with 123dB dynamic range performance with a low-noise, low-distortion, multibit delta-sigma (ΔΣ) ADC with a 113dB dynamic range. The dynamic range enhancer (DRE) is a digitally assisted algorithm to boost the overall channel performance. The DRE monitors the incoming signal amplitude and accordingly adjusts the internal DRE amplifier gain automatically. The DRE achieves a complete-channel dynamic range as high as 123dB. At a system level, the DRE scheme enables far-field, high-fidelity recording of audio signals in very quiet environments and low-distortion recording in loud environments.

The DRE is enabled only in target mode by driving high to the MD1 pin. Table 6-20 shows the DRE selection for the record channel.

Table 6-20 DRE Selection for the Record Channel
MD1 DRE SELECTION (Supported Only in Target Mode)
LOW DRE is disabled in target mode. For controller mode, DRE is always disabled.
HIGH DRE is enabled with DRE_LVL = –36dB and DRE_MAXGAIN = 24dB in target mode. For controller mode, DRE is always disabled.

This algorithm is implemented with very low latency and all signal chain blocks are designed to minimize any audible artifacts that may occur resulting from dynamic gain modulation. The target signal threshold level, DRE_LVL, at which DRE is triggered is fixed to the –36dB input signal level. The DRE gain range can be dynamically modulated by using DRE_MAXGAIN, which is fixed to 24dB to maximize the benefit of the DRE in real-world applications and to minimize any audible artifacts.

Enabling the DRE for processing increases the power consumption of the device because of increased signal processing. Therefore, disable the DRE for low-power critical applications. Furthermore, the DRE is not supported for output sample rates greater than 48kHz.