We are pleased to announce that as of August 13, 2015, Qualcomm Global Trading Pte. Ltd., a subsidiary of Qualcomm Incorporated, has completed its acquisition of CSR plc. For more information, please see the press release .


CSR8645™ is a Stereo ROM solution with aptX® codec technology and sets a new standard for wired or wireless stereo audio quality.  CSR8645 enables our customers to bring to market a range of highly differentiated home entertainment and wearable audio products - easily, quickly and cost effectively.  

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  •  Bluetooth® 4.1
  •  HFP1.6, A2DP1.2 and  AVRCP1.4
  •  HD voice (wideband speech)
  •  Wired Audio (USB and Analogue)
  •  AAC-LC, MP3 and SBC decoders
  •  Leading aptX® codec for high-quality audio
  •  Multi-band EQ (up to 6 x banks)
  •  Headphone stereo separation (soft 3D)
  •  iOS battery status monitor
  •  Smart Apps support (GAIA)
  •  Multi-Language programmable audio prompts
  •  Simple speech recognition
  •  Configurable LED drivers
  •  6th gen dual-mic cVc®   NR / AEC algorithms
    •  2-mic Far-end NR / AEC algorithms
    •  Frequency enhanced speech intelligibility (FESI)

Flexible ROM based platform

  •  Fully configurable MMI and tool chain

Package  options

  •  5.5x5.5mm, 68-pin BGA (0.5mm pitch)
  •  Pin compatible with CSR8640
Key Feature Value to the Customer Value to the User

High quality stereo music playback

aptX® = assured high quality music

Strong market success with aptX

Can extract higher market price

High quality music across Bluetooth, connecting with aptX source devices like TV’s, phones, tablets


Wired audio & full USB support

Wired as well as wireless

Extends use of headset to devices that don’t have Bluetooth

Can listen and charge – enjoy both a wireless and a wired experience – charge AND do

Multi-band EQ volume boost

Fully configurable & tunable EQ enabling multiple presets for Rock, Jazz, Classical, Dance etc

Dynamic bass boost.

Different types of music sound equally great.

Music doesn’t distort, even when it’s loud


Bi-directional noise reduction

NR benefit to the headset user.

Customer satisfaction with conversation quality

Conversation is clear and effortless

3 LEDs

Wide range of UI options.


Clearer and more extensive display of status information

Smart apps support with GAIA

Use Apps for product differentiation

Closer contact with end consumer using branded App

Create new revenue stream

Rich User experience

Interactive accessory via Apps

Personalisation via Apps


Bluetooth version


HFP Version


A2DP / AVRCP Version

1.2 / 1.4

Multipoint support

2 x HFP and 2 x A2DP

Multi-language programmable audio prompts

Supported in EEPROM or Serial Flash

Simple speech recognition (Yes / No)


Full RGB support


Battery Charger

Up to 200mA  internally

Up to 750mA using external BJT

iOS battery status monitor


Smart applications support (via GAIA)


AAC-LC, SBC, MP3 and faststream decoders


Configurable EQ banks (via PS keys)

Up to 6

Stereo separation (soft 3D)


Volume Boost


Wired audio support (USB and Analogue)


Package options

5.5x5.5mm BGA

CVC Version

CVC Version 6.0

Far end NR and full duplex AEC


Near  end audio enhancements with PLC / BEC


Packet loss / Bit error concealment


Ultra low-power wind noise reduction, superior voice quality


Side-tone filter up to 3 stage bi-quad user configurable


Increased noise reduction & voice quality


Wired USB mode


HFP1.6 support for WBS using the mSBC codec


Frequency enhanced speech intelligibility (FESI)


Wider mic separation distance (from 40mm to 200mm)


Tunable dual mic signal separation (DMSS) block


Initial gain & compression threshold parameters added AGC


Noise Dependant Power Saving (NDPS)


Increased AGC target level limits & gain limit


Increased AEQ power ratio limits (-90 to 15dB)


Digital microphone support


Terms of Supply

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