WM8281 Datasheet, PDF (1/392 Pages) Cirrus Logic – Low Power Audio System with Ambient Noise Cancellation and Echo Cancellation

WM8281
Low Power Audio System with
Ambient Noise Cancellation and Echo Cancellation
DESCRIPTION
The WM8281 is a highly-integrated low-power audio system for
smartphones, tablets and other portable audio devices. It
combines an advanced DSP feature set with a flexible, high-
performance audio hub CODEC.
The WM8281 digital core combines a quad-core, 600MMAC
DSP system with a variety of power-efficient fixed-function
audio processing blocks. The programmable DSP cores
support advanced audio features, including multi-mic wideband
noise reduction, high-performance acoustic echo cancellation
(AEC), stereo ambient noise cancellation (ANC), speech
enhancement, advanced media enhancement, and many more.
The DSP cores are supported by a fully-flexible, all-digital
mixing and routing engine with sample rate converters, for wide
use-case flexibility.
A SLIMbus^® interface supports multi-channel audio paths and
host control register access. Multiple sample rates are
supported concurrently via the SLIMbus interface. Three further
digital audio interfaces are provided, each supporting a wide
range of standard audio sample rates and serial interface
formats. Automatic sample rate detection enables seamless
wideband/narrowband voice call handover.
Three stereo headphone drivers each provide stereo ground-
referenced or mono BTL outputs. 110dB SNR, and noise levels
as low as 0.8μVRMS, offer hi-fi quality line or headphone output.
The WM8281 also features a stereo pair of 2W Class-D outputs
and four channels of stereo PDM output. A signal generator for
controlling haptics devices is included; vibe actuators can
connect directly to the Class-D speaker output, or via an
external driver on the PDM output interface. All inputs, outputs
and system interfaces can function concurrently.
The WM8281 supports up to eight microphone inputs, (up to
six analogue, or up to eight PDM digital, or combinations of
each). Microphone activity detection with interrupt is available.
A smart accessory interface supports most standard 3.5mm
accessories. Impedance sensing and measurement is provided
for external accessory and push-button detection.
The WM8281 power, clocking and output driver architectures
are all designed to maximise battery life in voice, music and
standby modes. Low-power ‘Sleep’ is supported, with
configurable wake-up events. The WM8281 is powered from a
1.8V external supply. A separate supply is required for the
Class D speaker drivers (typically direct connection to 4.2V
battery).
Two integrated FLLs provide support for a wide range of
system clock frequencies. The WM8281 is configured using the
I2C, SPI™ or SLIMbus interfaces. The fully-differential internal
analogue architecture, minimal analogue signal paths and on-
chip RF noise filters ensure a very high degree of noise
immunity.
FEATURES
 600 MIPS, 600MMAC multi-core audio-signal processor
 Programmable wideband, multi-mic audio processing
- Cirrus Logic^® stereo adaptive ambient noise cancellation
- Transmit-path noise reduction and echo cancellation
- Wind noise, sidetone and other programmable filters
- Dynamic Range Control, Fully parametric EQs
- Multiband Compression, Virtual Surround Sound
 Multi-channel asynchronous sample rate conversion
 Integrated 6/8 channel 24-bit hi-fi audio hub CODEC
- 6 ADCs, 100dB SNR microphone input (48kHz)
- 8 DACs, 121dB SNR headphone playback (48kHz),
(48kHz, eDRE software enabled)
 Audio inputs
- Up to 6 analogue or 8 digital microphone inputs
- Single-ended or differential mic/line inputs
 Multi-purpose headphone / earpiece / line output drivers
- 3 stereo output paths
- 33mW into 32Ω load at 1% THD+N
- 100mW into 16Ω BTL load at 5% THD+N
- 4mW typical headphone playback power consumption
- Pop suppression functions
- 0.8µVRMS noise floor (A-weighted)
 Stereo (2 x 2W) Class D speaker output drivers
- Direct drive of external haptics vibe actuators
 Four-channel digital speaker (PDM) interface
 SLIMbus audio and control interface
 3 full digital audio interfaces
- Standard sample rates from 4kHz up to 192kHz
- Ultrasonic accessory function support
- TDM support on all AIFs
- Multi-channel input/output on AIF1 and AIF2
- Stereo input/output on AIF3
 Flexible clocking, derived from MCLKn, BCLKn, LRCLKn or
SLIMbus
 2 low-power FLLs support reference clocks down to 32kHz
 Advanced accessory detection functions
- Low-power standby mode and configurable wake-up
 Configurable functions on 5 GPIO pins
 Integrated LDO regulators and charge pumps
 Small W-CSP package, 0.4mm pitch
APPLICATIONS
 Smartphones, tablets, and multimedia handsets
http://www.cirrus.com
Copyright  Cirrus Logic, Inc., 2014–2016
(All Rights Reserved)
Rev 4.0
MAR ‘16