SCHS463 May   2025 CD3268A , CD3269A

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  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
  7. 6 Parameter Measurement Information
    1. 6.1 eN-MIC Microphone Integrated Noise Measurement
    2. 6.2 Current Measurements
    3. 6.3 MICPWR Output Voltage Measurement
    4. 6.4 Tone Mode Threshold Measurements
    5. 6.5 Impedance Measurements
    6. 6.6 Tone Mode Output Measurements
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Tone Mode Start-up Timing
      2. 7.3.2 Authentication
      3. 7.3.3 Shunt Regulator
      4. 7.3.4 Power-on-reset
    4. 7.4 Device Functional Modes
      1. 7.4.1 Button Mode
      2. 7.4.2 Tone Mode
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Application Curves
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Device Support
      1. 9.1.1 Third-Party Products Disclaimer
      2. 9.1.2 Development Support
    2. 9.2 Receiving Notification of Documentation Updates
    3. 9.3 Support Resources
    4. 9.4 Trademarks
    5. 9.5 Electrostatic Discharge Caution
    6. 9.6 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

Package Options

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

7.3.3 Shunt Regulator

An internal shunt regulator in the CD326x isolates the internal circuitry power supply from the MIC pin. The shunt regulator can provide power to an external microphone module through the MICPWR pin, or the MICPWR output can be used as an enable signal to control power to an external microphone module as shown in Figure 8-1. The CD326x regulates the MICPWR output to approximately 1.56V. The shunt regulator only regulates the VSHUNT and MICPWR pins during tone mode. During button mode operation, the CD326x powers down the regulator. An external resistance between the MIC and VSHUNT pins determines the current into the VSHUNT pin. The shunt regulator requires current of at least 93µA to maintain regulation of the VSHUNT pin. Any excess current becomes available to the load at MICPWR. Any further excess current is internally shunted to ground.