WM8904 Overview
The WM8904 is a high-performance, ultra-low-power stereo codec featuring stereo ground-referenced headphone amplifiers that incorporate a dual-mode charge pump architecture to optimize efficiency and power consumption during playback. The ground-referenced headphone and line outputs eliminate AC coupling capacitors, and both outputs include common mode feedback paths to reject ground noise. Control sequences for audio path setup can be pre-loaded and executed by an integrated control write sequencer to reduce software driver development and minimize pops and clicks. The analog input stage can be configured for single ended, or differential inputs. Up to three stereo microphone or line inputs may be connected. The input impedance is constant with PGA gain setting. A stereo digital microphone interface is provided, with a choice of two inputs. A dynamic range controller provides compression and level control to support a wide range of portable recording applications. Anti-clip and quick release features offer excellent performance in the presence of loud impulsive noises. ReTune™ Mobile 5-band parametric equalizer with fully programmable coefficients is integrated for optimization of speaker characteristics. Programmable dynamic range control is also available for maximizing loudness, protecting speakers from clipping and preventing premature shutdown due to battery droop.
Product Features
3.0 mW quiescent power consumption for DAC to headphone playback
2.4 mW quiescent power consumption for analog bypass playback
DAC SNR 96 dB typical, THD –86 dB typical
ADC SNR 91 dB typical, THD –80 dB typical
Control write sequencer for pop minimized start-up and shutdown
Single register write for default start-up sequence
Integrated FLL provides all necessary clocks
Self-clocking modes allow processor to sleep
All standard sample rates from 8 kHz to 96 kHz
Stereo digital microphone input
3 single ended inputs per stereo channel
1 fully differential mic / line input per stereo channel
Digital Dynamic range controller (compressor / limiter)
Digital sidetone mixing
Ground-referenced headphone driver
Ground-referenced line outputs
32-pin QFN package (4x4mm, 0.4mm pitch)
36-ball WLCSP package (2.6 x 2.5mm, 6 x 6 ball grid, 0.4mm pitch)
Parametric Specifications
| Analog Input Type | Single-ended; Differential |
| Analog Output Type | Single-ended; Differential |
| Channels In | 2 |
| Channels Out | 2 |
| Control Interface | SPI/I²C |
| ADC Dynamic Range (dB) | 91 |
| DAC Dynamic Range (dB) | 96 |
| ADC THD+N (dB) | -80 |
| DAC THD+N (dB) | -86 |
| Sample Rate (kHz) | 8-96 |
| Analog Power Supply (V) | 1.71-2 |
| Digital Power Supply (V) | 1.2 |
| Logic Power Supply (V) | 1.8-3.3 |
| Power Consumption (mW) | 7.81-8.81 |
| Operational Power Consumption (mW) | 7.81-8.81 |
| Features | ReTune™ Mobile parametric EQ, dynamic range controller, DMIC interface, HP amp, FLL |
| Package | 32 QFN; 36 WLCSP |
Design Resources
WM8904CGEFL/V
WM8904ECS/R
WM8904 Datasheet
WM8904-6201-CS36-M-REV1 Example Configurations
WM8904-6201-FL32-M-REV1 Example Configurations
6201-EV1-REV3 Schematic and Layout
WM8904-6201-FL32-M-REV1 Schematic and Layout
DRC Attack and Decay Times for Real Audio Signals
DRC Operation in Wolfson Audio Codecs
External Component Requirements for Ground Referenced Outputs
Impedance Compensation for Ground Referenced Outputs
QFN Package PCB Footprint and Soldering Guidelines
Surface Mount Assembly Considerations for WLCSP Devices
Decoupling and Layout Methodology for Wolfson DACs, ADCs and Codecs
Evaluation Boards
WM8904 Evaluation Board (CDBWM8904-M-1)
Software Packages
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