Maxim公司的MAX98050是集成了低等待数字滤波器的低功耗高性能音频CODEC.器件具有单通路播放通路,具有5波段双二阶均衡器和高效率全差分混合AB类/D类耳机放大器.播放耳机放大器优化以得到极低输出噪音电平和最小化静态功耗,从而最大化输出功率效率.器件包括三个麦克风输入通路,支持声音,环境和抗噪音录音使用.每个通路能单独从外接模拟或数字麦克风进行录音,并能把音频数据送到录音通路(到数字音频接口)和外接低等待数字滤波器通路.还提供了第四个录音通路到数字音频接口,以允许主机监视播放通路输出数字数据.数字滤波器通路的取样速率96kHz/192kHz/384kHz可选择,单通路耳机播放通路具有高效的混合AB类/D类放大器,播放动态范围114dB,三个麦克风录音通路具有模拟或数字麦克风输入,动态范围107dB(AMIC单端)或113dB(AMIC差分).1% THD+N时32Ω的满刻度播放功率为31mW(1VRMS满刻度模式). 6.7mm2 36凸点WLP封装,主要用在真无线耳机和耳塞,立体声耳机,单声道蓝牙耳塞,PSAP设备和助听器辅助设备,VR/AR耳机和头带设备.本文介绍了MAX98050主要优势和特性,简化和详细框图,PCM输入和输出音频数据通路图,PCM模式录音和播放应用电路图以及评估系统MAX98050EVSYS#主要特性,单声道和立体声框图,评估板电路图,材料清单和PCB设计图.

The MAX98050 is a low-power, high-performance audio CODEC with integrated low-latency digital filters for wire­less hearables, headsets, and headphones.

The device features a mono playback channel with a 5-band biquad equalizer and a high-efficiency, fully differ­ential hybrid class-AB/class-D headphone amplifier. The playback headphone amplifier is optimized for extremely low output noise levels and minimized quiescent power consumption while maximizing output power efficiency.

The device includes three microphone input channels ca­pable of supporting voice, ambient, and anti-noise record use cases. Each channel can individually record from ei­ther an external analog or digital microphone, and then can route audio data to both the record channels (to the digital audio interface) and the internal low-latency digital filter channels. A fourth record channel to the digital audio interface is provided to allow the host to monitor the play­back channel output digital data.

Two low-latency, digital filter channels are provided that can support a variety of use cases. These include noise cancellation applications (feed-forward, feedback, and hy­brid filter profiles), both voice and ambient enhancement and transparency applications, and sidetone applications. Each channel provides a 12-band digital biquad filter, a DRC or Limiter stage, a digital volume control block, and an ultrasound filter. In addition, a third internal digital filter channel is provided in the playback channel that is struc­tured for playback compensation and/or general feedback compensation filters. This channel includes a 10-band bi­quad filter and a digital volume control block. To support dynamic or adaptive filter and use case transitions, the bi­quad filters and volume controls provide banked profiles that can be updated/swapped without disruption to audio playback.

The flexible digital audio interface supports common PCM audio data formats such as I2S, left-justified, and TDM tim­ing with 16-bit, 24-bit, or 32-bit data word and channel lengths. The PCM interface supports playback sample rates from 8kHz to 192kHz and record sample rates from 8kHz to 48kHz. The device requires external bit and frame clocks but eliminates the need for a high-speed external master clock.

The device is available in a small 6.7mm2 36-bump WLP package (0.4mm pitch) with a low 0.5mm height ideal for tight form factors. The device operates over the extended -40C to +85C temperature range.

MAX98050主要优势和特性:

● Low-Latency Digital Filter Channels

• 96kHz/192kHz/384kHz Sample Rate Options

• Channel Support Applications Including Feed-Forward (FF) and Feedback (FB) ANC, Ambient/Voice Enhancement and Transparency, and Playback Compensation

• Filters Allowing Smooth, Dynamic Transitions / Updates without Playback Disruption

● Mono Headphone Playback Channel

• High-Efficiency Hybrid Class-AB/D Amplifier

• 114dB Playback Dynamic Range

• 2.55mW PQ (fS = 48kHz, No Noise Gate)

• 1.9mW PQ (fS = 48kHz, With Noise Gate)

● Three Microphone Record Channels

• Analog or Digital Microphone Inputs

• 107dB Dynamic Range (AMIC Single-Ended)

• 113dB Dynamic Range (AMIC Differential))

• 5.3mW PQ (fS = 16kHz, 2 AMIC Record)

• 2.1mW PQ (fS = 16kHz, 2 DMIC Record)

● Playback with ANC Filter Profile (fS = 192kHz)

• 9.85mW PQ (AMIC FF+FB Profile)

• 6.7mW PQ (AMIC FF Only Profile)

• 7mW PQ (DMIC FF+FB Profile)

● Full-Scale Playback Power at 1% THD+N:

• 31mW into 32Ω (1VRMS Full-Scale Mode)

• 15mW into 32Ω (Reduced Swing Mode)

• 61mW into 16Ω (1VRMS Full-Scale Mode)

● Flexible I2S/TDM Digital Audio Interface

• Support for 16/24/32-Bit Audio Data

• Playback Sample Rates of 8kHz to 192kHz

• No High-Speed Master Clock Required

● Audio CODEC Evaluation Platform Available

• Includes Maxim Reference Headset Design

● 6.7mm2 36-Bump WLP Package

• 0.4mm Pitch with a 0.5mm Height

MAX98050应用:

● True Wireless Hearables and Headsets

● Stereo Bluetooth Headsets and Headphones

● Mono Bluetooth Earpieces

● PSAP Devices and Hearing Assist Devices

● VR/AR Headsets and Head-Mounted Devices

图1.MAX98050简化框图

图2.MAX98050详细框图

图3.MAX98050 PCM输入和输出音频数据通路图

图4.MAX98050 PCM模式录音和播放应用电路图

评估系统MAX98050EVSYS#

The MAX98050 evaluation system (MAX98050EVSYS#) evaluates the MAX98050, a low-power, high-performance audio CODEC with integrated low-latency digital filters for wireless hearables, headsets, and headphones. The EV system is comprised of two MAX98050 Development Boards (DEV boards), Maxims Audio Interface Board III (AUDINT3), Maxims Dual EVKit Adapter board, and a USB cable. In addition to the hardware, the MAX98050 Evaluation Software and Hearable Sound Studio Basic software are available for download.

It is recommended that the DEV boards be evaluated with the AUDINT3 board as an EV system. The EV system can be configured as Mono Hardware Setup (1 DEV board) or Stereo Hardware Setup (2 DEV boards). MAX98050 supports standard I2S, left-justified, and TDM digital audio interfaces, as well as I2C for control.

The AUDINT3 board provides all of the necessary supply voltages for proper operation of MAX98050. In addition, the AUDINT3 provides the USB-to-PCM and USB-to-I2C interfaces that are needed to evaluate the system. The Simplified EV System Block Diagrams show details of the DEV boards, Dual EVKit Adapter board and connection with the AUDINT3 board.

For GUIs, there is the MAX98050 Evaluation Software, which provides complete access to all hardware registers. There is also the Hearable Sound Studio Basic software, which facilitates the tuning of the onboard 5 band play­back equalizer, digital filter channels, and the digital filter dynamic range compression (DRC).

评估系统MAX98050EVSYS#主要优势和特性:

Complete Hardware System with Easy Setup, No Tools or Special Equipment Required

Easy-to-Use Graphical User Interfaces Software (Windows® 10 Compatible) MAX98050 Evaluation Software Provides Complete Access to All Hardware RegistersHearable Sound Studio Basic for Digital Filter Design and Acoustic Hardware Evaluation.

评估系统MAX98050EVSYS#包括:

Two MAX98050 Development Boards (DEV Boards)

Audio Interface Board III (AUDINT3)

Dual EVKit Adapter Board

Micro-USB cable

图5.评估系统MAX98050EVSYS#简化框图:单通道硬件建立

6.评估系统MAX98050EVSYS#简化框图:立体声硬件建立

7.评估系统MAX98050EVSYS#电路图(1)

8.评估系统MAX98050EVSYS#电路图(2)

9.评估系统MAX98050EVSYS#电路图(3)

评估系统MAX98050EVSYS#材料清单:

10.评估系统MAX98050EVSYS# PCB设计图(1):顶层

11.评估系统MAX98050EVSYS# PCB设计图(2):内层2(地)

12.评估系统MAX98050EVSYS# PCB设计图(3):内层3(信号)

13.评估系统MAX98050EVSYS# PCB设计图(4):内层4(地)

14.评估系统MAX98050EVSYS# PCB设计图(5):内层5(地)

15.评估系统MAX98050EVSYS# PCB设计图(6):底层

16.评估系统MAX98050EVSYS# PCB设计图(7):底层综合