Module Bluetooth music receiver BTM334 (QCC3034) + PCM5121, QCC303X Bluetooth Receiver, a Bluetooth music receiver made based on the BTM334 module, which can also be used as a USB sound card. This Bluetooth receiver uses the BTM334 Bluetooth module and utilizes the module’s I2S as the audio output. The DAC used is TI’s PCM5121, which supports USB sound card functionality.

The block diagram of the Bluetooth receiver is as follows:

The Bluetooth module uses Qualcomm’s QCC3034 chip, which supports standard SBC and AAC encoding, as well as Qualcomm’s own aptX, aptX-HD, and aptX-LL encoding, ensuring the quality of Bluetooth audio.
It can also be connected to a computer via USB as a USB sound card, plug and play, supporting up to 16bit/48k. The DAC (digital-to-analog converter) uses a PCM5121 chip from TI, which features a built-in charge pump to generate negative power supply, allowing for output without coupling capacitors. It supports hardware control/SPI/I2C and has fixed audio processing functions, supporting up to 32bit/384k, with a 2VRMS output. In my personal opinion, the sound quality is good.
(However, I only used the H/W Mode and wasted most of the features of this chip, which is a pity.) For power supply, two LDOs are used, with AZ1117 responsible for powering the Bluetooth module and ME6211, a high-speed and high PSRR LDO, responsible for powering the DAC to ensure a clean power supply.

Schematic Module Bluetooth music receiver BTM334 (QCC3034) + PCM5121

The USB interface uses the extremely convenient type-C, which can be selected between power supply only and power supply + USB sound card function based on the insertion direction (Note: If the receiver is already connected to the computer and Bluetooth is connected to a phone, long press the Play/Pause button for a few seconds to disconnect the Bluetooth connection and enable the USB sound card function).
The board has 3 tactile switches, with functions for play/pause, previous track/volume-, and next track/volume+.
Long pressing the play button will disconnect the Bluetooth connection. The board also reserves an I2S interface (through the ZH1.5-5pin connector, as defined in the schematic).

Regarding sound quality: can hardly hear any background noise, the sound is clear, and the resolution is quite high. It does not drag or muddy the sound, and it sounds better than the built-in CODEC of computers/phones. It’s quite touching.

About QCC3034

The QCC3034 is a highly advanced system-on-chip (SoC) developed by Qualcomm for wireless audio devices. It is specifically designed to provide a superior audio experience with its cutting-edge features and technologies. The QCC3034 offers seamless connectivity options, supporting Bluetooth 5.2 and Qualcomm aptX Adaptive audio technology, ensuring high-quality audio transmission and low latency. Additionally, it boasts an integrated quad-core processor, delivering powerful performance and efficient power consumption. The SoC also supports active noise cancellation (ANC) and voice assistant integration, enhancing the user experience further. Overall, the QCC3034 is a remarkable SoC that empowers wireless audio devices with exceptional audio quality, connectivity, and advanced features.

Problems/Improvements encountered during production:

• The definition of the headphone jack caused only the left channel to produce sound. We had to perform a small operation on the board, connecting a wire from the board to the right channel of the headphone jack. After this modification, both left and right channels produced sound normally. The modified schematic of the headphone interface is shown in the figure below.

• In addition to using PCM512x (PCM5121, 5122) as the DAC chip, we can also use PCM510xA (such as PCM5102A). The latter does not have SPI, I2C, DSP, but has the same functionality. When soldering, align pin 1 of PCM510xA with the solder pad on the PCB that is indicated by the triangle (the same as PCM512x and PCM510xA pin 1).
• Besides using BTM334 as the Bluetooth module, it can also be replaced with the following modules, which are completely pin-to-pin compatible, although some functionality differences may exist.

Applicable to the following modules:

• BTM320(QCC3020)
• BTM324(QCC3024)
• BTM334(QCC3034)
• BTM524(QCC5124)
• BTM525(QCC5125)
• BTM526(QCC5126)

Note: BTM320 (QCC3020) is a mono audio output, without SPK BP/SPK BN pins. BTM320/BTM324/BTM334 do not support SPDIF input/output.

The datasheet and other reference materials used in the design of this Bluetooth receiver will be included in the links e notes.

Bom Module Bluetooth music receiver BTM334 (QCC3034) + PCM5121

Download files, links, and notes

Download PCB in Gerber, PDF, PNG, SVG
Download

Mirror

• Buy BTM334 Bluetooth module
• PDF datasheet IC PCM2151— PCM512x 2-VRMS DirectPath™, 112-dB and 106-dB Audio Stereo DACs With 32-Bit, 384-kHz PCM Interface datasheet (Rev. C)
• BTM32x/BTM33x/BTM52x Bluetooth module application schematic
• PCM512x/4x EVM User’s Guide (Rev. A)—PCM5122EVM-U and PCM5142EVM-U

Source: https://oshwhub.com/xyzDIY/qcc303x-lan-ya-jie-shou-qi