ST Life.augmented


Scalable digital microphone processor
  • active Active

The STA321MP is a PDM high-performance multichannel processor with ultra-low quiescent current designed for general-purpose digital microphone applications. The device is fully digital and is comprised of three main sections. The first section is the PDM input interface which can accept up to six serial digital inputs. The second section is a high-quality audio processor allowing flexible channel mixing/muxing and provides up to 10 biquads for general sound equalization and voice enhancement with independent volume control. The last block is the I²S output interface which streams out the processed digital audio. The output interface can also be programmed for flexible channel mapping. The device offers some of the most commonly required audio enhancements such as programmable voice tuning and equalization, limiter/compressor for improved voice quality, multiband selection for customizable microphone usage and configurable wind-noise rejection. The embedded digital processor allows offloading the microphone processing from the main CPU or SoC, moving it to the device.

The STA321MP has six digital microphone inputs, providing connections for up to three dual-membrane microphones.

pdf Please read
Errata Sheet
pdf Download

Key Features

  • 8 digital processing channels each 24-bit
  • 6 channels of PDM input
  • 2 additional virtual channels
  • >100 dB SNR and dynamic range
  • Digital gain/attenuation +58 dB to -100 dB in 0.5 dB steps
  • Soft volume update
  • Individual channel and master level control
  • Up to 10 independent 32-bit user-programmable biquads (EQ) per channel
  • Bass/treble tone control
  • Pre- and post-EQ full 8-channel input mix on all 8 channels
  • Dual independent limiters/compressors
  • Dynamic range compression or anti-clipping modes
  • Individual channel and master soft/hard mute
  • 3 I²S data outputs
  • I²S data output channel mapping function
  • Independent channel volume and DSP bypass
  • Channel mapping of any input to any processing channel

Design Resources


Technical Documentation

Product Specifications

Description Version Size
DS8825: Scalable digital microphone processor
5.0 2,469 KB

Application Notes

Description Version Size
AN3340: Loudspeaker characterization and compensation
1.3 3,944 KB
AN3984: IIR filter design equations for Sound Terminal® devices
1.1 494 KB
AN4146: STSmartVoice demonstration board STEVAL-MKI126Vx
2.0 3,511 KB

Presentations & Training Material

Training Material

Description Version Size
Learn the basics about STSpeakerSafe technology
1.0 181 KB

Related Tools and Software

Related Tools and Software

Part Number Description
STEVAL-MKI126V2 MEMS microphone evaluation board based on STA321MPL and MP34DB01 (microphone processor + digital uPhone MEMS)

Publications and Collaterals


Description Version Size
ST’s solutions for mobile devices
2,855 KB

Sample & Buy

Part Number Marketing StatusPackagePacking TypeOperating Temperature (min) Operating Temperature (max) Automotive GradeOrder From STUnit Price (US$)*
@ 1000
Distributor AvailabilityRoHS Compliance GradeDownload
Material Declaration**
STA321MPLTRActiveLQFP 64 10x10x1.4Tape And Reel-4090_-3.551Distributor reported inventory date: 2016-02-29
Distributor NameRegionStockMin. order
STA321MPTRPreviewVFQFPN 59 8x8x0.9Tape And Reel-4090_-No availability reported, please contact our Sales officeEcopack2-

(*) Suggested Resale Price per unit (USD) for BUDGETARY USE ONLY. For quotes, prices in local currency, please contact your local ST Sales Office or our Distributors
(**) The Material Declaration forms available on may be generic documents based on the most commonly used package within a package family. For this reason, they may not be 100% accurate for a specific device. Please contact our sales support for information on specific devices.