WM8944 Overview
The WM8944 is a highly integrated low-power hi-fi codec designed for portable devices such as digital still cameras. Up to 2 analog inputs may be connected, and a stereo digital microphone interface is also provided. Flexible output mixing options support single-ended and differential configurations, with outputs derived from the digital audio paths or from analog bypass paths. Mono line output and mono BTL headphone/speaker drive is supported. Flexible digital mixing and powerful DSP functions are available. Programmable filters and other processes may be applied to the ADC and DAC signal paths simultaneously. The DSP functions include 5 notch filters, 5-band EQ, dynamic range control and the Cirrus Logic ReTune™ feature. The ReTune™ feature is a sophisticated digital filter that can compensate for imperfect characteristics of the housing, loudspeaker or microphone components in an application. The ReTune™ algorithm can provide acoustic equalization and selective phase (delay) control of specific frequency bands. The WM8944 is controlled via a I²C or SPI interface. Additional functions include digital beep generator, video buffer, programmable GPIO functions, Frequency Locked Loop (FLL) for flexible clocking support and integrated LDO for low noise supply regulation. The WM8944 is supplied in 25-ball W-CSP package, ideal for portable systems.
Product Features
Hi-fi audio codec
94 dB SNR during ADC recording (‘A’ weighted)
96 dB SNR during DAC playback (‘A’ weighted)
2 analog audio inputs
Integrated bias reference for electret microphones
Digital microphone interface (Stereo)
Powerful digital mixing / DSP functions:
5-notch filters
5-band equalizer (EQ)
ReTune™ parametric filter
Dynamic range control and noise gate
Low-pass/High-pass filters
Direct Form 1 (DF1) programmable digital filter
3D stereo enhancement (for digital mic input)
Digital beep generator
Mono line output
Mono BTL headphone/speaker output driver
I²S digital audio interface - sample rates 8 kHz to 48 kHz
Frequency Locked Loop (FLL) frequency conversion / filter
Video buffer function
Integrated LDO low-noise voltage regulator
25-ball W-CSP package (2.38 x 2.38 x 0.7mm, 0.5mm pitch)
Parametric Specifications
| Analog Input Type | Single-ended; Differential |
| Analog Output Type | Single-ended; Differential |
| Channels In | 1 |
| Channels Out | 1 |
| Control Interface | SPI/I²C |
| ADC Dynamic Range (dB) | 94 |
| DAC Dynamic Range (dB) | 96 |
| ADC THD+N (dB) | -77 |
| DAC THD+N (dB) | -78 |
| Sample Rate (kHz) | 8-48 |
| Analog Power Supply (V) | 2.4-3.6 |
| Digital Power Supply (V) | 1.8 |
| Logic Power Supply (V) | 1.8-3.3 |
| Power Consumption (mW) | 9.9-54.7 |
| Features | AUX ADC, battery monitor |
| Package | 25 WLCSP |
Design Resources
WM8944B Datasheet
6229-EV1-REV2 Schematic and Layout
WM8944B-6229-CS25-M-REV1 Schematic and Layout
WM894X-6229-CS36-M-REV1 Example Configurations
DRC Operation in Wolfson Audio Codecs
Implementing ReTune with Wolfson Audio Codecs
Decoupling and Layout Methodology for Wolfson DACs, ADCs and Codecs
Software Packages
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