Wolfson公司的WM8994是高度集成智能手機(jī)用超低功耗高保真音頻CODEC,具有高保真24位4路DAC和2路ADC,立體聲DAC播放的SNR為100dB(A加權(quán)),1W立體聲/2W單聲道D類/AB類揚(yáng)聲器驅(qū)動器,無電容W類耳機(jī)驅(qū)動器,智能的MIC接口和高性能模擬MIC接口,主要應(yīng)用在智能手機(jī)和音樂手機(jī),手提導(dǎo)航儀和移動互聯(lián)網(wǎng)設(shè)備(MID).本文介紹了WM8994主要特性,方框圖, 采用數(shù)字MIC和數(shù)字音頻接口的智能手機(jī)方框圖以及WM8994評估板,功能方框圖,詳細(xì)電路圖和所用材料清單(BOM).
The WM8994 is a highly integrated ultra-low power hi-fi CODEC designed for smartphones and other portable devices rich in multimedia features.
An integrated stereo class D/AB speaker driver and class W headphone driver minimize power consumption during audio playback.
The device requires only Vbatt and a 1.8V supply, generating all other internal supply rails from integrated LDOs.
Stereo full duplex asynchronous sample rate conversion and multi-channel digital mixing combined with powerful analogue mixing allow the device to support a huge range of different architectures and use cases.
A fully programmable parametric EQ provides speaker compensation and a dynamic range controller can be used in the ADC or DAC paths for maintaining a constant signal level, maximizing loudness and protecting speakers against overloading and clipping.
A smart digital microphone interface provides power regulation, a low jitter clock output and decimation filters for up to four digital microphones. A MIC activity detect with interrupt is available.
Active ground loop noise rejection and DC offset correction help prevent pop noise and suppress ground noise on the headphone outputs.
WM8994主要特性:
• Hi-Fi 24-bit 4-channel DAC and 2-channel ADC
• 100dB SNR during stereo DAC playback (‘A’ weighted)
• Smart MIC interface
- Power, clocking and data input for up to four digital MICs
- High performance analogue MIC interface
- MIC activity monitor & interrupt allows processor to sleep
• 1W stereo / 2W mono class D/AB speaker driver
• Capless class W headphone drivers
- Integrated charge pump
- 6mW total power for DAC playback to headphones
• 4 line outputs (single-ended or differential)
• BTL earpiece driver
• Digital audio interfaces for multi-processor architecture
- Asynchronous stereo duplex sample rate conversion
- Powerful mixing and digital loopback functions
• ReTuneTM Mobile 5-band, 6-channel parametric EQ
• Programmable dynamic range controller
• Dual FLL provides all necessary clocks
- Self-clocking modes allows processor to sleep
- All standard sample rates from 8kHz to 96kHz
• Active noise reduction circuits
- DC offset correction removes pops and clicks
- Ground loop noise cancellation
• Integrated LDO regulators
• 72-ball W-CSP package (4.511mm x 4.023mm x 0.7mm)
WM8994應(yīng)用:
• Smartphones and music phones
• Portable navigation
• Mobile internet devices
![](http://solution.eccn.com/uploads/solution/201007/20100702105459197.gif)
圖1.WM8994方框圖
![](http://solution.eccn.com/uploads/solution/201007/20100702105500561.gif)
圖2.采用數(shù)字MIC和數(shù)字音頻接口的WM8994智能手機(jī)方框圖
WM8994評估板
The WM8994 is a highly integrated ultra-low power hi-fi CODEC designed for smartphones and other portable devices rich in multimedia features. This evaluation platform has been designed to allow the user ease of use and give optimum performance in device measurement as well as providing the user with the ability to listen to the excellent audio quality offered by the WM8994.
![](http://solution.eccn.com/uploads/solution/201007/20100702105500572.gif)
圖3.WM8994評估板功能方框圖
![](http://solution.eccn.com/uploads/solution/201007/20100702105501957.gif)
圖4.WM8994評估板電路圖:S/PDIF接口
![](http://solution.eccn.com/uploads/solution/201007/20100702105503271.gif)
圖5.WM8994評估板電路圖:USB接口
![](http://solution.eccn.com/uploads/solution/201007/20100702105505739.gif)
圖6.WM8994評估板電路圖:控制I/F電平轉(zhuǎn)移
![](http://solution.eccn.com/uploads/solution/201007/20100702105505104.gif)
圖7.WM8994評估板電路圖:音頻I/F電平轉(zhuǎn)移
![](http://solution.eccn.com/uploads/solution/201007/20100702105506146.gif)
圖8.WM8994評估板電路圖:音頻輸入
![](http://solution.eccn.com/uploads/solution/201007/20100702105506639.gif)
圖9.WM8994評估板電路圖:DUT插座
![](http://solution.eccn.com/uploads/solution/201007/20100702105507694.gif)
圖10.WM8994評估板電路圖:音頻輸出
![](http://solution.eccn.com/uploads/solution/201007/20100702105507915.gif)
圖11.WM8994評估板電路圖:GPIO接口
![](http://solution.eccn.com/uploads/solution/201007/20100702105508605.gif)
圖12.WM8994評估板電路圖:USB電源1
![](http://solution.eccn.com/uploads/solution/201007/20100702105508268.gif)
圖13.WM8994評估板電路圖:USB電源2
![](http://solution.eccn.com/uploads/solution/201007/20100702105509644.gif)
圖14.WM8994評估板電路圖:外接電源
![](http://solution.eccn.com/uploads/solution/201007/2010070210550997.gif)
圖15.WM8994評估板電路圖:Mini板ID
WM8994評估板材清單(BOM):
![](http://solution.eccn.com/uploads/solution/201007/20100702105511822.gif)
![](http://solution.eccn.com/uploads/solution/201007/20100702105512426.gif)
![](http://solution.eccn.com/uploads/solution/201007/20100702105514924.gif)
![](http://solution.eccn.com/uploads/solution/201007/20100702105515779.gif)
![](http://solution.eccn.com/uploads/solution/201007/20100702105515395.gif)
|