Module Bluetooth music receiver BTM334 (QCC3034) + PCM5121

Bluetooth music receiver BTM334 QCC3034 PCM5121

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:

Bluetooth Music Receiver Btm334 (Qcc3034) + Pcm5121 Clock Diagram
Btm334 Diagram Block

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.

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Schematic Module Bluetooth music receiver BTM334 (QCC3034) + PCM5121

Schematic 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.

Btm334 Audio Input

  • 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.
Bluetooth Music Receiver Btm334 Qcc3034 Pcm5121 Pcb
Bluetooth Music Receiver Btm334 Qcc3034 Pcm5121 Pcb

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

Value Name Description Quantity
22uF C1A,C1B 0805 – SMD Ceramic capacitor 2
CAP-SMD_L3.5-W2.8-R-RD C20,C21 Tantalum capacitor CASE B (3528) 2
0.1uF C16,C4,C6,C8,C9 C0603 – SMD Ceramic capacitor 5
10uF C14,C15 0805 – SMD Ceramic capacitor 2
2.2uF C2,C3 0603 – SMD Ceramic capacitor 2
10uF C5,C7 0603 – SMD Ceramic capacitor 2
2.2n C10,C11 0603 – SMD Ceramic capacitor 2
1uF C12,C13 0603 – SMD Ceramic capacitor 2
BTM334/525 U1 BTM334 Bluetooth module 1
PCM5121PW U2 TSSOP-28 – Audio Stereo DACs With 32-Bit
384-kHz PCM Interface
AZ1117EH-3.3TRG1 U3 1A Fixed 3.3V Positive 13V SOT-223 1
ME6211C33M5G-N U4 500mA Fixed 3.3V Positive 6V SOT-23-5
Linear Voltage Regulators
LED-0603_R LED1 0603 Red LED 1
LED-0603_B LED2 0603 Blue LED 1
22R (220) R1,R2,R3,R4 0402 – SMD resistor 4
0R (0) R5 0805 – SMD resistor 1
470R (471) R6,R7 0603 – SMD resistor 2
1k (102) R8,R9,R10,R11,R13,R14 0603 – SMD resistor 6
100k (104) R12 0603 – SMD resistor 1
0R (0) L1,L2 0603 – SMD Resistor 2
0R (0) L3 0805 – SMD Resistor 1
UK-B0230-G3.7-250 PAUSE/PLAY,VOL+/NEXT,VOL-/PREV No NO 50mA 100 MΩ 12V Brick nogging
SPST SMD Tactile Switches
CONN-TH_5P-P1.50_HCTL_C-ZH1.5-5AW J1 1.5 mm 5 pin connector 1
IPEX-SMD_BWIPX-1-001E ANT BWIPX-1-001E – 1 Inner needle IPEX Board Edge 6GHz 50Ω
SMD RF Connectors / Coaxial Connectors
TYPE-C16PIN USB1 3A 1 Surface Mount 16P Female Type-C SMD USB Connectors 1

Download files, links, and notes

Bluetooth Music Receiver Btm334 Qcc3034 Pcm5121 Pcb 3D
Pcb 3D

Download PCB in Gerber, PDF, PNG, SVG



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About the author blog author. Electronics technician for the technical school of Brasilia - Brazil. Interested in electronics, circuits and technology in general.

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