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2 x 100 mW class-D amplifer with analog or digital input, 2.0 multichannel digital audio processor with FFX
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The STA529 is a digital stereo class-D audio amplifier. It includes an audio DSP, an ST proprietary high-efficiency class-D driver and CMOS power output stage. It is intended for high-efficiency digital-to-power-audio conversion for portable applications. The STA529 also provides output capabilities for FFX. In conjunction with a power device, the STA529 provides high-quality digital amplification.

The STA529 contains an on-chip volume/gain control.

The PWM amplifier achieves greater than 90% efficiency for longer battery life for portable systems.

The innovative class-D modulation, allows the STA529 to work without external LC filters and without a heatsink.

The STA529 I2CDIS pin disables the audio DSP functions and the I2C interface provides a direct conversion of the input signal into output power. This conversion is done without the microcontroller.

The STA529 is designed for low-power operation with extremely low-current consumption in standby mode. It is available in packages TFBGA48 and VFQFPN52. These are very thin packages (1.2 mm thick) ideal for small portable applications.

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Key Features

  • Up to 96 dB dynamic range
  • Sample rates from 8 kHz to 192 kHz
  • FFXclass-D driver
  • 1.55 V to 1.95 V digital power supply
  • 1.80 V to 3.60 V analog and I/O power supply
  • 18-bit audio processing and class-D FFXmodulator
  • >90-dB SNR analog-to-digital converter
  • Digital volume control:
  • +36 dB to -105 dB in 0.5-dB steps
  • Software volume update
  • 16-bit ADC
  • Individual channel and master gain/attenuation
  • Automatic invalid input detect mute
  • 2-channel I2S input/output data interface
  • Digitally controlled pop-free operation
  • 90% efficiency
  • Output power for stereo headphones or stereo speakers applications (at THD = 10% and VCC= 3.3 V):
  • 45 mW with 32-Ω headphones
  • 85 mW with 16-Ω headphones
  • 720 mW with 8-Ω speakers
  • 1.1 W with 4-Ω speakers

Circuit Diagram

Design Resources


Technical Documentation

Product Specifications

Description Version Size
DS5050: FFX™ audio codec with analog and digital inputs and 2 x 1.2 W (or 2 x 100 mW HP) class-D amplifier
3.0 509 KB
DB0353: 2 x 100 mW class-D amplifier with analog or digital input 2.0 multichannel digital audio processor with FFX
1.3 81 KB

Application Notes

Description Version Size
AN2542: Demo board BT-HTS-Rx_V1.0 for audio receiver using Bluetooth® wireless technology
2.2 766 KB
AN2612: How to use the BT_HTS_RX_R2 evaluation board
1.2 1,684 KB
AN3340: Loudspeaker characterization and compensation
1.3 3,944 KB
AN3984: IIR filter design equations for Sound Terminal® devices
1.1 494 KB
AN4118: APWLink USB interface board for Sound Terminal® demonstration boards
2.0 1,029 KB

User Manual

Description Version Size
UM0457: How to use the BT_HTS_RX_R2
1.2 377 KB
UM1545: Using the Audio Processor Workbench (APWorkbench)
1.0 3,221 KB

Presentations & Training Material


Description Version Size
Sound Terminal audio ICs
1.0 322 KB

Training Material

Description Version Size
Learn the basics about STSpeakerSafe technology
1.0 197 KB

Publications and Collaterals


Description Version Size
APWorkbench software for audio ICs and MEMS microphones
2,349 KB
Sound Terminal for portable audio
201 KB


Description Version Size
Analog audio solution
1.0 1,371 KB
FFX - Full flexible amplification
4,722 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**
STA529QActiveVFQFPN2 52 8x8x1.0Tray070_-2.841No availability reported, please contact our Sales officeEcopack2PDF

(*) 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.
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