PCM1864-Based Circular Microphone Board (CMB) Reference Design


Design files


The PCM1864 circular microphone board (CMB) is a low-cost easy-to-use reference design for applications that require clear-spoken audio, such as voice triggering and speech recognition. This TI Design uses a microphone array to capture a voice signal, and converts it to a digital stream that can be used by DSP systems to extract clear audio from noisy environments.

  • Uses two PCM1864 4-channel audio ADCs to interface with eight microphone arrays to extract clear speaker voice from noisy environments
  • EnergySense notification for signal presence and loss – central part of a low-power, high-performance audio solution
  • Offers a complete system reference design using microphone array, TI-provided software, and evaluation module
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A fully assembled board has been developed for testing and performance validation only, and is not available for sale.

Design files & products

Design files

Download ready-to-use system files to speed your design process.

TIDUD37.PDF (608 K)

Reference design overview and verified performance test data


Detailed schematic diagram for design layout and components


Complete listing of design components, reference designators, and manufacturers/part numbers


Detailed overview of design layout for component placement

TIDRQT7.ZIP (18998 K)

Files used for 3D models or 2D drawings of IC components

TIDCDE5.ZIP (6085 K)

Design file that contains information on physical board layer of design PCB

TIDRQT6.ZIP (10228 K)

PCB layer plot file used for generating PCB design layout


Includes TI products in the design and potential alternatives.

Audio ADCs

PCM1864103dB 4-Channel Software-Controlled Audio ADC With Universal Front End

Data sheet: PDF | HTML
Noninverting buffers & drivers

SN74LVC1G125Single 1.65-V to 5.5-V buffer with 3-state outputs

Data sheet: PDF | HTML
Noninverting buffers & drivers

SN74LVC1G126Single 1.65-V to 5.5-V buffer with 3-state outputs

Data sheet: PDF | HTML

Technical documentation

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Type Title Date
* Design guide PCM1864 Based Circular Microphone Board Reference Design Apr. 10, 2017
Certificate PCM1864CMBEVM EU Declaration of Conformity (DoC) Jan. 02, 2019

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