Consumer Electronics / Audio / TWS Earbuds
TWS Earbuds Electronics: BES2710 Platform Schematic Reconstruction and a Reusable Audio Block Library
For an Indian consumer-audio brand we rebuilt a BES2710 true-wireless earbud platform as a verified KiCad schematic (87 parts, 55 nets, 0 ERC errors) and set up a reusable block library for its audio range. Status: schematic delivered August 2026.
Indian consumer-audio brandJuly–August 2026Rapid Circuitry hardware team
Published Last reviewed:
Illustrative imageThe Challenge
The brand sells true-wireless earbuds, soundbars, speakers and home-theatre systems, and wanted to own well-documented electronics for its range instead of treating every product as a one-off. For the earbuds, it needed a trustworthy schematic of the Bluetooth SoC platform: a sound basis for design changes and new models.
Reference material is hard to reuse
Vendor hardware kits ship reference schematics as drawings and layout files, not as an editable, checked schematic in the brand's own tools.
Impact: No editable master schematicEvery product treated as a one-off
Re-documenting each earbud, soundbar and speaker from scratch repeats the same power, radio and audio circuits many times over.
Impact: Repeated effort per SKUSmall errors are costly
A 4 × 4 mm, 0.35 mm-pitch SoC package leaves no room for a wrong pin or net. A schematic read by eye is not good enough to lay out from.
Impact: Needs proof, not inspectionLicensed technology boundaries
Some products use licensed audio decoding. The work had to stay within hardware and firmware and never touch licensed algorithms.
Impact: Licence-safe scopeOur Solution
We reconstructed the SoC vendor's earbud reference design as a hierarchical KiCad schematic and proved its connectivity three independent ways. In parallel we defined a company-wide library of reusable schematic blocks so future products can be assembled from validated blocks, with new work scoped only to what changes.
System Architecture
What the reconstructed BES2710 earbud platform contains, organised as reusable blocks.
Power and charging
- Single-inductor, dual-output buck: core rail 0.6–0.9 V and I/O/audio rail 1.6–2.0 V
- Internally generated supplies decoupled at the SoC; no extra regulators
- Charger 5 V and one-wire UART share one pad behind TVS and Schottky clamps
- Download UART runs at 1.8 V logic
Audio and sensing
- Three analog MEMS microphone channels: feedback, feed-forward and talk
- Mic bias with RC filtering; AC-coupled inputs
- Capacitive touch channels with series resistors
- NTC temperature divider sharing a touch GPIO
Radio and package
- π-matched RF path to a printed meander antenna
- Crystal layout rules that protect ESD performance
- QFN-36, 4 × 4 mm, 0.35 mm pitch; custom footprint drawn from the datasheet
Schematic Facts
| Bluetooth audio SoC | Bestechnic BES2710 (QFN-36) |
| Components | 87 |
| Nets | 55 |
| Hierarchical sheets | 7 block sheets |
| ERC (KiCad 10) | 0 errors, 2 intentional warnings |
| Outputs | KiCad project, PDF, netlist, BOM, design notes |
What We Delivered
- Hierarchical KiCad schematic of the BES2710 earbud platform
- Rendered PDF, netlist and two BOM formats
- Design notes covering power, charging, audio, touch and RF
- Custom footprint for the 0.35 mm-pitch QFN-36
- List of open items to confirm against the production BOM
- Hardware and firmware reverse-engineering plans for the earbud and soundbar lines
- Modular block-library strategy covering all four product categories
- Engagement options, from schematic-and-BOM only to full replication
Key Engineering Decisions
What we chose, and why.
Prove connectivity mechanically
The reference drawings are vector PDFs
Rebuilt every connection from wire segments, junction dots and off-page ports
Grouping of all 36 SoC pins matched the KiCad netlist exactly
Cross-check with the vendor's layout netlist
The vendor's layout file holds a machine-readable netlist
Supply and key signal nets matched, with the same reference designators
Also confirms parts were mapped to the right symbols
Report deltas, don't hide them
Evaluation board vs reference design
Two supply pins are tied on one and separate on the other
Flagged for a decision before layout
Build blocks, not products
Power, radio, audio output, input and control blocks
A block enters the library only with a sheet, interface spec, BOM with alternates and validation tag
Success measure: share of each new product built from existing blocks
Outcome and Status
The earbud platform schematic was delivered in August 2026 with zero ERC errors and connectivity proven three independent ways. Some items still need confirming against the production BOM, such as a few bead-or-link positions and passive package sizes, and these are listed in the delivery.
Connectivity
55 / 55 nets
Matched by manual trace, an independent re-derivation and a mechanical proof
Electrical rule check
0 errors
KiCad 10; the 2 warnings are intentionally unused touch channels
Vendor cross-check
Matched
Key supply and signal nets agree with the vendor's layout netlist
Technologies Used
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