WT2605B03 Bluetooth Audio Module
Dual‑Mode Bluetooth 5.0 with MP3 Playback, Built‑in 1W Amplifier & UART Control
The WT2605B03 is a high‑performance dual‑mode Bluetooth 5.0 audio module designed for wireless audio and MP3 playback applications. Powered by a 32‑bit DSP, it features a 16‑bit DAC with 96dB SNR and a 16‑bit ADC with 90dB SNR for pristine audio quality. With a built‑in 1W Class‑D amplifier, UART control (115200 baud), and support for SPI‑Flash, TF card, and USB drive storage, it is the ideal solution for Bluetooth speakers, car audio, and smart home devices.
- Dual‑mode BT 5.0 – audio + BLE
- MP3 playback – local storage playback
- Built‑in 1W amp – direct 8Ω speaker drive
- 16‑bit DAC – 96dB SNR for superior output
- UART control – simple command set
Key Features
Audio & Bluetooth Specifications
| Parameter | Value |
|---|---|
| DAC Resolution | 16‑bit |
| DAC SNR | 96 dB (A‑Weighted) |
| DAC THD+N | ‑86 dB |
| DAC Max Output | 2.6 Vpp (32Ω loading) |
| ADC Resolution | 16‑bit |
| ADC SNR | 90 dB (A‑Weighted) |
| ADC THD+N | ‑87 dB |
| Sample Rates | 8, 11.025, 12, 16, 22.05, 32, 44.1, 48 kHz |
| Bluetooth Version | 5.0 (BR/EDR + BLE) |
| Bluetooth Profiles | A2DP, AVRCP, HFP, SPP, GATT |
| RF Output Power | +2 dBm (typical) |
| Audio Formats | MP3 (≤44.1kHz, ≤320kbps), WAV (≤44.1kHz, ≤320kbps) |
| Storage Media | SPI‑Flash (128Mbit), TF (32GB), USB (32GB) |
| Amplifier Output | 1W @ 8Ω (Class‑D) |
UART Command Highlights
| Command | Function | Description |
|---|---|---|
| A0 | Index Flash Playback | Play by index in SPI‑Flash |
| A2/A3 | TF Card Playback | By index or filename |
| A6/A7 | USB Playback | By index or filename |
| A4/A5 | Folder Playback | TF card folder by index or filename |
| A8/A9 | Folder Playback | USB folder by index or filename |
| AA | Pause / Resume | Toggle pause |
| AB | Stop | Stop playback |
| AC/AD | Next / Previous | Track navigation |
| AE | Volume Control | 0–31 (default 26) |
| AF | Playback Mode | Normal / Single loop / All loop / Folder loop |
| B1 | Insert Playback | Insert a track during playback |
| B2 | EQ Format | Normal / Pop / Rock / Jazz / Classic / Bass |
| B3/B4 | Get Duration | Total / current playback time (TF/USB) |
| BB | Switch Mode | Bluetooth ↔ MP3 (local playback) |
| BC/BD | Call Control | Answer / end call |
| BF | Disconnect BT | Disconnect Bluetooth connection |
| C0–C2 | Queries | Version, volume, status |
| C5–C9 | File Queries | File count on TF/USB, current track |
| CB | Song Name | Current song name (MP3 mode) |
| CC | Flash Track Count | Total tracks in Flash |
| D1–D3 | Bluetooth Name | Change/query name and MAC |
| E2–E5 | Delete Files | Delete by index or filename |
| E7 | Copy from USB | Copy audio from USB to Flash |
| FF 05 | Extended Commands | BLE data, song info, phonebook, etc. |
Protocol format: 7E + Length + Command + Parameters + Checksum + EF. Return codes: 0x00 = OK, 0xFE = format error, 0xFF = execution error.
Technical Specifications
| Parameter | Value / Condition |
|---|---|
| Module Size | 21.21 × 18.24 × 3.35mm (±0.3mm) |
| Pin Pitch | 2.0mm |
| Processor | 32‑bit DSP |
| Operating Voltage | 3.3V – 5.0V |
| DAC SNR | 96 dB (A‑Weighted) |
| ADC SNR | 90 dB (A‑Weighted) |
| Audio Formats | MP3 (≤44.1kHz, ≤320kbps), WAV (≤44.1kHz, ≤320kbps) |
| External Storage | SPI‑Flash (128Mbit), TF (32GB), USB (32GB) |
| Control Interface | UART (115200 baud) |
| Volume Levels | 32 (0–31, default 26) |
| Bluetooth | 5.0, dual‑mode (BR/EDR + BLE) |
| Bluetooth Name | BT_WT2605 (audio), LE_WT2605 (BLE) |
| Crystal | 26MHz, 11pF, ±10PPM |
| Amplifier Output | 1W @ 8Ω (Class‑D) |
| Operating Temperature | ‑40°C ~ +85°C |
| IO Drive Capability | 8 mA |
Pin Functions (20‑Pin Module)
| Pin | Name | Function |
|---|---|---|
| 2 | SDCMD / SPICS | TF internal CS / SPI‑Flash CS |
| 3 | SPK+ | Speaker positive (1W @ 8Ω) |
| 4 | SPK− | Speaker negative |
| 5 | DACR | DAC right channel output |
| 6 | DACL | DAC left channel output |
| 9 | MIC | Microphone input |
| 11 | MP3_EN | Flash chip select control |
| 12 | TXD | UART transmit |
| 13 | RXD | UART receive |
| 14 | SDCLK / SPISCLK | TF clock / Flash clock |
| 15 | PWRKEY | AD key input |
| 16 | VDDIO | 3.3V digital power |
| 17 | SDDAT / SPIDAT | TF data / Flash data |
| 18 | VBAT | Power input (3.3–5.0V) |
| 19 | DM | USB D− |
| 20 | DP | USB D+ |
Chip package: SSOP24. SPI and SD card share pins – they cannot be used simultaneously. The PWRKEY function requires custom firmware – contact Waytronic for details.
Application Scenarios
Why Choose WT2605B03
Frequently Asked Questions
What is the WT2605B03?
WT2605B03 is a dual-mode Bluetooth 5.0 audio module with built-in MP3 playback, 1W Class-D amplifier, 16-bit DAC (96dB SNR) and ADC (90dB SNR), UART control, and support for SPI-Flash, TF card, and USB storage.
What Bluetooth profiles are WT2605B03 supported?
WT2605B03 supports A2DP, AVRCP, HFP, and BLE (GATT) profiles for music streaming, remote control, hands-free calling, and data transmission.
What is the Bluetooth name?
The default audio Bluetooth name is ‘BT_WT2605’ and the BLE name is ‘LE_WT2605’. Both can be changed via serial commands.
What storage media are WT2605B03 supported?
WT2605B03 supports SPI-Flash up to 128Mbit, TF card up to 32GB, and USB drive up to 32GB. The chip can switch between Bluetooth mode and MP3 mode for local playback.
What is the audio quality?
WT2605B03 features a 16-bit DAC with 96dB SNR and a 16-bit ADC with 90dB SNR, delivering high-quality audio input and output.
Does WT2605B03 have a built-in amplifier?
Yes. WT2605B03 features a built-in 1W Class-D amplifier that can directly drive an 8Ω speaker, with 32-level volume control.
What control interface does it use?
It uses a standard UART interface with default baud rate 115200. Commands follow a 7E … EF protocol for playback, volume, EQ, and BLE control.
What is the operating voltage range?
The chip operates from 3.3V to 5.0V, compatible with both 3.3V and 5V systems.
What is the recommended Bluetooth range?
The recommended range is within 10 meters for optimal performance. Proper PCB layout and antenna design are required.
What are the typical applications?
Bluetooth speakers, stereo headsets, car audio systems, smart home devices, voice recorders, and any application requiring wireless audio streaming with local storage playback.
Important: A 26MHz crystal (11pF, ±10PPM) is required for Bluetooth operation. SPI‑Flash and SD card share the same pins – they cannot be used simultaneously. The chip defaults to Bluetooth mode on power‑up; use the BB command to switch to MP3 mode. For external Flash, Waytronic‑branded Flash is recommended. The PWRKEY function and phonebook features require custom firmware – contact Waytronic for details. The USB interface can function as a sound card, but Bluetooth audio is disabled in that mode. Command interval should be ≥200ms after power‑up.
