Maxim公司的MAX98380是集成容性升壓轉換器的小型單聲道數字輸入D類音頻放大器.器件具有基于三倍電荷泵升壓轉換器,能向8Ω負載提供高達1% THD+N的4.85W功率.容性升壓替代所需的大和貴的電感,以降低總PCB解決方案.此外由于電池壽命降低而引起電源電壓變化,片上限制器(DHT)自動優化D類放大器的可用凈空高度,以維持一致性失真和聽覺水平.當器件的熱限制達到時熱折返保護保證了魯棒性能,而當溫度超過用戶指定的閾值時器件能自動降低輸出功率.這就使得在高環境溫度時不間斷的音樂播放.除了穩健的過電流保護,傳統的熱保護也可提供.器件提供用于音頻數據的PCM接口和用于控制數據通信的I2C接口.PCM接口支持采用I2S,左對準和TDM音頻數據格式的音頻播放.獨特的時鐘結構消除了用于PCM通信的外接主時鐘.除了降低尺寸和引腳數量,還降低EMI和可能的板耦合問題. VBAT = 3.7V時6Ω負載的輸出功率為3.6W,總靜態功耗為10mW,80%效率(RL = 8Ω時1.0W, VBAT = 3.7V).工作溫度-40°C 到+85°C.主要用在智能手機,智能揚聲器,IoT設備和平板電腦.本文介紹了MAX98380主要優勢和特性,簡單框圖和詳細框圖, 典型應用電路圖和評估系統MAX98380 EVS主要特性,電路圖,材料清單和PCB設計圖.
The MAX98380 is a small, mono Class-D audio amplifier featuring an integrated capacitive boost converter. The device implements a tripler charge pump-based boost converter that efficiently delivers up to 4.85W at 1% THD+N into an 8Ω load. The capacitive boost replaces the large and expensive inductor required for an inductive boost with smaller, lower-profile capacitors that reduce the total PCB solution.
Additionally, as the power-supply voltage varies due to declining battery life, an on-chip limiter (DHT) automatically optimizes the headroom available to the Class-D amplifier to maintain consistent distortion and listening levels.
Thermal-foldback protection ensures robust behavior when the thermal limits of the device are reached. When enabled, it automatically reduces the output power when the temperature exceeds a user-specified threshold. This allows for uninterrupted music playback even at high ambient temperatures. Traditional thermal protection is also available in addition to robust overcurrent protection.
The device provides a PCM interface for audio data and a standard I2C interface for control data communication. The PCM interface supports audio playback using I2S, left-justified, and TDM audio data formats. A unique clocking structure eliminates the need for an external master clock for PCM communication. This reduces EMI and possible board coupling issues in addition to reducing the size and pin count.
Active emissions-limiting and edge-rate limiting 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 IC is available in a 0.35mm pitch 24-bump wafer-level package (WLP). It is specified over the extended, -40°C to +85°C temperature range.
MAX98380主要優勢和特性:
● Integrated Capacitive Boost Converter—No Bulky Inductors
● 3.6W Output Power into 6Ω at VBAT = 3.7V
● 10mW Total Quiescent Power
● 3ms Turn-On Time
● 80% Efficiency (1.0W into RL = 8Ω, VBAT = 3.7V)
● 19.8μVRMS Speaker Mode Output Noise
● 16.5μVRMS Receiver Mode Output Noise
● Low 0.005% THD+N at 1kHz
● No MCLK Required
● Sample Rates of 8kHz to 192kHz
● Supports Left, Right, or (Left/2 + Right/2) Output in I2S and Left-Justified Modes
● Sophisticated Edge Rate Control Enables Filterless Class-D Outputs
● Low RF Susceptibility Rejects TDMA Noise from GSM Radios
● Class-D Switching Frequency Trimmed to 10% for Better EMI Planning
● Extensive Click-and-Pop Reduction Circuitry
● Dynamic Headroom Tracking (DHT)
● Robust Short-Circuit and Thermal Protection
● Available in Space-Saving Package: 1.468mm x 2.138mm, 24-Bump WLP (0.35mm Pitch)
MAX98380應用:
● Smartphones
● Smart Speakers
● IoT Devices
● Tablets
圖1. MAX98380簡化框圖
圖2. MAX98380詳細框圖
圖3. MAX98380典型應用電路圖
評估系統MAX98380 EVS
The MAX98380 evaluation system (EV system) is a fully assembled and tested system that evaluates the MAX98380 boosted Class-D audio amplifier. The EV system consists of the MAX98380 Development Board (DEV board), Analog Devices Audio Interface Board III (AUDINT3), and a USB cable.
It is recommended that the DEV board be evaluated with the AUDINT3 board, as an EV system. The MAX98380 supports standard I2S, left-justified, and TDM digital audio interfaces.
The AUDINT3 board provides a USB-to-PCM interface in addition to a 1.8V VDD supply needed to evaluate the DEV board. The MAX98380 DEV board requires one additional supply input, 2.5V to 5.5V (VBAT) when evaluating using the AUDINT3 board. Figure 1 details the DEV board and the AUDINT3 board.
評估系統MAX98380 EVS主要特性:
2.5V to 5V Single-Supply Operation
USB Audio Streaming (EV System)
I2S, Left-Justified, or TDM Input
Capacitive Charge Pump Boost Circuitry
Fully Assembled and Tested
評估系統MAX98380 EVS包括:
MAX98380 Development Board
Audio Interface Board III
Micro-USB Cable
圖4. 評估系統MAX98380 EVS外形圖
圖5. 評估系統MAX98380 EVS電路圖
評估系統MAX98380 EVS材料清單:
圖6. 評估系統MAX98380 EVS PCB設計圖:左:頂層絲印;右:層2
圖7. 評估系統MAX98380 EVS PCB設計圖:左:頂層布局;右:層3
圖8. 評估系統MAX98380 EVS PCB設計圖:左:層4;右:底層
圖9. 評估系統MAX98380 EVS PCB設計圖:左:層5;右:底層絲印 |
