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| MAX98357A PCM輸入D類音頻放大器解決方案 |
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| 文章來源：永阜康科技 更新時間：2017/9/14 14:54:00 |
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Maxim公司的MAX98357A/MAX98357B是數(shù)字脈碼調(diào)制(PCM)輸入D類放大器,提供AB類音頻性能和D類效率,有五個可選擇的增益設定(3dB, 6dB, 9dB, 12dB和15dB),單電源2.5V-5.5V工作,5V 4Ω時的輸出功率為3.2W,效率92% (RL = 8Ω, POUT = 1W),輸出噪音25μVRMS (AV = 15dB),1kHz時的THD+N為0.015%,主要用在筆記本電腦和上網(wǎng)本(Netbook),手機和平板電腦.本文介紹了MAX98357A/MAX98357B主要特性,功能框圖和幾種應用電路,以及MAX98357開發(fā)板DEV(WLP)主要特性,框圖,電路圖,材料清單和PCB設計圖.
The MAX98357A/MAX98357B are digital pulse-code modulation (PCM) input Class D power amplifiers that provide Class AB audio performance with Class D efficiency. These ICs offer five selectable gain settings (3dB, 6dB, 9dB, 12dB, and 15dB) in I2S/left-justified mode set by a single gain select input and a fixed 12dB gain in TDM mode.
The digital audio interface is highly flexible with the MAX98357A supporting I2S data and the MAX98357B supporting left-justified data. Both ICs support 8 channel time division multiplexed (TDM) data. The digital audio interface accepts specified sample rates between 8kHz and 96kHz for all supported data formats. The ICs can be configured to produce a left channel, right channel, or (left/2 + right/2) output from the stereo input data. The ICs operate using 16/24/32-bit data for I2S and left-justified modes as well as 16-bit or 32-bit data using TDM mode. The ICs eliminate the need for the external MCLK signal that is typically used for PCM communication. This reduces EMI and possible board coupling issues in addition to reducing the size and pin count of the ICs.
The ICs also feature a very high wideband jitter tolerance (12ns typ) on BCLK and LRCLK to provide robust operation.Active emissions-limiting, edge-rate limiting, and overshoot control circuitry greatly reduce EMI. A filterless spread-spectrum modulation scheme eliminates the need for output filtering found in traditional Class D devices and reduces the component count of the solution.
The ICs are available in 9-pin WLP (1.345mm x 1.435mm x 0.64mm) and 16-pin TQFN (3mm x 3mm x 0.75mm) packages and are specified over the -40 ℃ to +85℃ temperature range.
MAX98357A/MAX98357B主要特性:
Single-Supply Operation (2.5V to 5.5V)
3.2W Output Power into 4Ω at 5V
2.4mA Quiescent Current
92% Efficiency (RL = 8Ω, POUT = 1W)
25μVRMS Output Noise (AV = 15dB)
Low 0.015% THD+N at 1kHz
No MCLK Required
Sample Rates of 8kHz to 96kHz
Supports Left, Right, or (Left/2 + Right/2) Output
Sophisticated Edge Rate Control Enables Filterless Class D Outputs
77dB PSRR at 1kHz
Low RF Susceptibility Rejects TDMA Noise from GSM Radios
Extensive Click-and-Pop Reduction Circuitry
Robust Short-Circuit and Thermal Protection
Available in Space-Saving Packages: 1.345mm x 1.435mm WLP (0.4mm Pitch) and 3mm x 3mm TQFN
MAX98357A/MAX98357B應用:
Notebook and Netbook Computers
Cellular Phones
Tablets
圖1.MAX98357A/MAX98357B功能框圖
圖2.MAX98357A/MAX98357B增益6dB左路PCM工作電路
圖3.MAX98357A/MAX98357B增益12dB左路PCM工作電路
圖4.MAX98357A/MAX98357B增益6dB右路PCM工作電路
圖5.MAX98357A/MAX98357B增益6dB(左路/2+右路/2)PCM工作電路
圖6.MAX98357A/MAX98357B采用兩個IC的立體聲PCM工作電路
圖7.MAX98357A/MAX98357B增益12dB通路TDM工作電路
MAX98357開發(fā)板DEV(WLP)
The MAX98357 development board (DEV board) is a fullyassembled and tested PCB that evaluates the MAX98357I2S digital input Class D power amplifier. The DEV boardoperates from a single 2.5V to 5.5V DC power supply andis capable of delivering 3.2W into a 4Ω load. The deviceoutputs can be connected directly to a speaker load forfilterless applications. However, a filter can be added toease evaluation. The MAX98357A accepts standard I2Sdata and the MAX98357B accepts left-justified digital audio data. Both versions also support 8-channel TDMaudio data.
The MAX98357 evaluation system (EV system) includesthe MAX98357 DEV board and Maxim Integrated’s audiointerface board (AUDINT001 board).
The AUDINT001 board provides an easy-to-use USBaudio-to-I2S converter. This allows for any computer tobecome a digital audio source, which can be used toevaluate the devices. The AUDINT001 board can also beused to power the MAX98357. This allows for a completeevaluation from a single USB connection.
MAX98357開發(fā)板DEV(WLP)主要特性:
●● 2.5V to 5.5V Single-Supply Operation
●● Only a Single External Component (VDD Capacitor)Required in Many Applications
●● I2S, Left-Justified, or TDM Input
●● Five Selectable Gains (3db, 6dB, 9dB, 12dB, and15dB)
●● Audio Channel Select (Left, Right, and Mono Mix)
●● Filterless Operation
●● Optional Class D Output Filters for Ease ofEvaluation
●● Proven PCB Layout
●● Fully Assembled and Tested
圖8.MAX98357開發(fā)板DEV(WLP)簡化框圖
圖9.MAX98357開發(fā)板DEV(WLP)電路圖
MAX98357開發(fā)板DEV(WLP)材料清單:
圖10.MAX98357開發(fā)板DEV(WLP) PCB設計圖(1)
圖11.MAX98357開發(fā)板DEV(WLP) PCB設計圖(2)
圖12.MAX98357開發(fā)板DEV(WLP) PCB設計圖(3)
圖13.MAX98357開發(fā)板DEV(WLP) PCB設計圖(4)
圖14.MAX98357開發(fā)板DEV(WLP) PCB設計圖(5) |
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