CSR8645 Bluetooth 4.0 - APT-X MP3 AAC FastStream - Breakout Board

Experience has shown that most / all bluetooth modules available on the market have problems of various kinds. Is it generating noise, receiving noise, have a poor coverage and/or bad audio quality.

This CSR8645 based module provides

Specification

  • Input voltage range 5.5-40V (TPS7A6601), 5.0V (USB)
  • alternative 6.0 60V (TPS54061) with flybuck and isolated linedriver supply
  • trouble-free operation
  • DSP/EQ (Kalimba DSP)
  • 2Vrms output level - unbalanced via 3.5 mm jack or 1 × 3 pin headers per DRV602 linedriver
  • Balanced direct DAC output
  • unbalanced input (AUX line) via a 3.5mm jack socket
  • AAC, MP3, APT-X, FastStream
  • USB audio (optional)
  • Programming via USB without dedicated USB-SPI programmer
  • 5 button (optional); also available on 1 × 7 connector
  • 3 LED (optional)
  • 10 GPIO at 1 × 12 connector
  • 1V8 <-> 3V3 levelshift for SPI/programmer
  • u.FL antenna connector
  • and, when using an external antenna, approx. 40m range

Hardware

CSR8645 breakout board hardware #1

CSR8645 breakout board hardware #1

CSR8645 breakout board hardware #1

CSR8645 breakout board hardware #1

AGML battery charger

Measurements

Loopback EMU 0202 (reference)
Loopback spectrum 1 kHz 96 kHz 3dBV EMU 0202

Loopback spectrum 1 kHz 96 kHz 3dBV EMU 0202

Loopback modulation   distortion 96 kHz 6dBFS EMU 0202

Loopback modulation distortion 96 kHz 6dBFS EMU 0202

Loopback Distortion THD 1kHz 96kHz -6dBFS EMU-0202

Loopback distortion THD 96 kHz 6dBFS EMU 0202

Static noise
Spectrum 96kHz EMU-0202 - Static Noise

Spectrum 96 kHz EMU 0202 - static noise

1 kHz spectrum via BT link
Spectrum 1 kHz 96 kHz 6dBV BT link

Spectrum 1 kHz 96 kHz 6dBV BT link

Spectrum 1kHz 96kHz -3dBV BT-Link

Spectrum 1kHz 96kHz -3dBV BT-Link

Spectrum 1kHz 96kHz 6dBV BT-Link

Spectrum 1kHz 96kHz 6dBV BT-Link

1 kHz spectrum via AUX line-in
Spectrum 1kHz 96kHz -3dBV AUX Line-In

Spectrum 1kHz 96kHz -3dBV AUX Line-In

Spectrum 1kHz 96kHz 3dBV AUX Line-In

Spectrum 1kHz 96kHz 3dBV AUX Line-In

Modulation Distortion – Aux Line-In

Modulation Distortion 96kHz -3dBV AUX Line-In

Modulation Distortion 96kHz -3dBV AUX Line-In

Distortion THD 96kHz -3dBV AUX Line-In

Distortion THD 96kHz -3dBV AUX Line-In

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14 Responses

  1. Chris says:

    Is the flybuck converter selected to drive this board if I for example; use this in a boombox and have noise/groundloop issues? Or is the PSRR of the TPS7A6601 enough for this application?

    • 360customs says:

      Correct, thats what it is for. The main problem is ground loop related when looking at a fully build amp. These BT-ICs conduct some noise when grounding/layout/wiring is bad. For this there are two solutions implemented on this board. 1st the flybuck, 2nd the DRV602 Linedriver with ground-loop-breaker. See TI AN SLOA143.
      GroundLoopBreakCircuitsandTheirOperation

      Until now i haven’t needed the flybuck, it always worked with the DRV602 alone. Seems like the layout isn’t that bad. 🙂

      Regards, Christian

  2. Jens Geisler says:

    That looks fantastic and is actually the only thing that is commensurate with the chip. Is there somewhere to buy the board? Or Schematics + BOM?

  3. Alexander Jaworowski says:

    If you have a board, then I gladly buy it. I can even buy two boards if available.

    Best,
    Alexander

  4. Herschdorfer,,nl,3. January 2018,,en,15:48,,en,Chang Huawei VT SMD Capacitors – Datasheet (Downloads: 356),,en says:

    Hi nice work.
    Im currently working on a hobby project for the F3188.
    Its a hard time to find documentation about this.

    Is there any chance you could share the schematics or some documentation of the F3188?

  5. semeral says:

    Hi, I picked this thread on diyaudio.com forum, and I would like to ask if this board will be up for sale? I would pretty much prefer this over questionable breakouts from alixpress…

  6. Did you actually try to program the this one?
    How would you go about programming it?

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