原标题：ADI SSM35822x31.76 W数字输入无滤波器D类放大器解决方案

　　ADI公司的SSM3582是2x31.76 W高效数字输入无滤波器立体声D类放大器,可以工作在单电源,仅需要很少的外接元件,从而大大降低了电路的材料清单.器件采用扩频Σ-Δ调制,能直接和扬声器连接,和其它D类架构相比,保证了最好的模拟性能而同时降低了电磁辐射,可选择超低电磁干扰(EMI)模式,大大降低了100MHz以上的辐射,从而可以使用更长的扬声器电缆.放大器具有杰出的模拟性能,信噪比为106dB,总失真+噪音(THD+N)为0.004%. SSM3582A工作电压为单电源4.5 V 到16 V ,能向8 Ω 和4 Ω负载以小于1% THD提供2x15W rms连续功率.功率效率8 Ω负载为93.8%,4 Ω负载为90.6%.脉码调制(PCM)音频串口支持大多数协议如I2S,左侧调整, 时分复接(TDM),以及单个接口上寻址多达16个器件,多达32个音频播放通路.器件具有短路保护,欠压保护和热保护.主要用在移动计算,全合一计算机,手持电子学,无线扬声器和电视机.本文介绍了SSM3582主要特性,功能框图和立体声和单声道放大器应用电路,以及评估板EVAL-SSM3582Z主要特性,框图,电路图,材料清单和PCB设计图.

　　The SSM3582A is a fully integrated, high efficiency, digital input stereo Class-D audio amplifier. The device can operate from a single supply and requires only a few external components, significantly reducing the circuit bill of materials.

　　A proprietary, spread spectrum Σ-Δ modulation scheme enables direct connection to the speaker and ensures state-of-the-art analog performance while lowering radiated emissions compared to other Class-D architectures. An optional ultralow electromagnetic interference (EMI) mode significantly reduces radiated emissions above 100 MHz, enabling longer speaker cable lengths. Audio is transmitted digitally to the amplifier, minimizing the possibility of signal corruption in digital environments. The amplifier provides outstanding analog performance, with a 106 dB signal-to-noise ratio and a low 0.004% total harmonic distortion + noise (THD + N).

　　The SSM3582A operates from a single 4.5 V to 16 V supply and is capable of delivering 2× 15 W rms continuously into 8 Ω and 4 Ω loads at <1% total harmonic distortion (THD). The efficient modulation scheme maintains excellent power efficiency over a wide range of impedances: 93.8% into an 8 Ω load and 90.6% into a 4 Ω load. Optimization of the output pulse maintains performance at impedances as low as 3 Ω/5 μH, enabling its use with extended bandwidth tweeters.

　　The pulse code modulation (PCM) audio serial port supports most common protocols, such as I2S, left justified, and time division multiplexing (TDM), and can address up to 16 devices on a single interface, for up to 32 audio playback channels.

　　IC operation is controlled through a dedicated I2C interface. The two ADDRx pins (2×, five-level) define up to 16 individual addresses in I2C and standalone modes and automatically set the default TDM slots attribution.

　　A micropower shutdown mode is triggered by removing the digital audio interface clock, with a typical current of <1 μA. A software power-down mode is also available.

　　An automatic power-down feature shuts down the amplifier and the digital-to-analog converter (DAC) when no signal is present at the input, minimizing power consumption during digital silence. The device restarts when nonzero data is present at the input. Mute and unmute transitions are pop and click free.

　　The SSM3582A is specified over the commercial temperature range of −40℃to +85℃. The device has built in thermal shutdown and output short-circuit protection, as well as an early thermal warning with programmable gain limiting to maintain operation.

　　The SSM3582A is available in a 40-lead, 6 mm × 6 mm lead frame chip scale package (LFCSP), with a thermal pad to improve heat dissipation.

　　SSM3582主要特性:

　　Digital input stereo, high efficiency Class-D amplifier

　　Operates from a single 4.5 V to 16 V supply

　　State-of-the-art, proprietary, filterless Σ-Δ modulation

　　106.5 dB SNR at PO = 8.1 W, RL = 8 Ω, AV = 19 dB, PVDD = 12 V, A weighted

　　0.004% THD + N at 5 W into 8 Ω

　　38.5 μVrms output voltage noise, f = 20 Hz to 20 kHz, A weighted, PVDD = 16 V, 8 Ω

　　Pop and clickless on and off sequence

　　2× 14.67 W output at 12 V supply to 4 Ω loads at <1% THD + N

　　2× 14.4 W output at 16 V supply to 8 Ω loads at <1% THD + N

　　Mono mode for increased maximum output power

　　1× 49.69 W output at 16 V supply to 2 Ω loads at <1% THD + N

　　Support for low impedance loads

　　As low as 3 Ω/5 μH in stereo mode

　　As low as 2 Ω/5 μH in mono mode

　　High power efficiency

　　93.8% efficiency into an 8 Ω load

　　90.6% efficiency into a 4 Ω load

　　12.34 mA quiescent current with single 12 V PVDD supply

　　Single-supply operation with internal LDOs or option to use an external 5 V and 1.8 V supply for lowest power consumption

　　I2C control and hardware modes with up to 16 pin-selectable slots/addresses

　　Supported sample rates from 8 kHz to 192 kHz with 24-bit resolution

　　Multiple PCM audio serial data formats

　　TDM slave with support for up to 16 devices on a single bus

　　I2S or left justified slave

　　Adjustable full-scale output tailored for many PVDD sources

　　2- and 3-cell Li-Ion batteries

　　Digital volume control with selectable smooth ramp

　　Automatic power-down function

　　Supply monitoring automatic gain control (AGC) function reduces system brownout

　　Standalone operational mode without I2C

　　Temperature sensor with 1°C step readout via I2C

　　Short-circuit, undervoltage, and thermal protection

　　Thermal early warning

　　Power-on reset

　　PVDD sensing ADC

　　40-lead, 6 mm × 6 mm LFCSP with thermal pad

　　SSM3582应用:

　　Mobile computing

　　All in one computers

　　Portable electronics

　　Wireless speakers

　　Televisions

　　图1.SSM3582功能框图

　　图2.SSM3582立体声输出应用电路图

　　图3.SSM3582单声道输出应用电路图

　　评估板EVAL-SSM3582Z

　　Evaluating the SSM3582 or the SSM3582A 2×, 31.76 W, Digital Input, Filterless Stereo ClassD Audio Amplifier

　　The EVAL-SSM3582Z is the evaluation board for the SSM3582 or the SSM3582A, integrated stereo, 31.76 W, high efficiency, Class D, audio amplifiers with a digital input. This evaluation board can be used for both the SSM3582 or the SSM3582A devices.

　　The application circuit requires few external components and can operate from a single 4.5 V to 16 V supply. The EVAL-SSM3582Z is capable of delivering 14.67 W of continuous output power to a 4 Ω load from a 12 V power supply, with <1% THD + N, or 31.76 W into a 4 Ω load from 16 V, 10% THD + N.

　　The SSM3582 and the SSM3582A feature a high efficiency, low noise modulation scheme that requires no external reconstruction filter (LC) output filters. This scheme provides high efficiency, even at low output power.

　　The EVAL-SSM3582Z and the SSM3582 or the SSM3582A operate with 93.8% efficiency at 10 W into an 8 Ω load or 90.6% efficiency at 18 W into 4 Ω load from a 12 V supply. The EVAL-SSM3582Z, the SSM3582, and the SSM3582A have a typical noise floor of 38.5 μVrmsA weighted.

　　This user guide describes how to configure and use the EVAL-SSM3582Z. Read this user guide in conjunction with the SSM3582 and the SSM3582A data sheets, which provide specifications, internal block diagrams, a register map, and application guidance for the amplifiers.

　　评估板EVAL-SSM3582Z主要特性:

　　2×, 31.76 W into 4 Ω at16 V, THD + N = 10%

　　EVALUATION KIT CONTENTS

　　USBi USB interface board

　　USB cable

　　EVAL-SSM3582Z evaluation board

　　图4.评估板EVAL-SSM3582Z外形图(正面)

　　图5.评估板EVAL-SSM3582Z外形图(背面)

　　图7.评估板EVAL-SSM3582Z框图电路

　　图8.评估板EVAL-SSM3582Z电路图:SSM3582部分

　　图9.评估板EVAL-SSM3582Z电路图:数字输入部分

　　图10.评估板EVAL-SSM3582Z电路图:电源部分

　　图11.评估板EVAL-SSM3582Z电路图:输出部分

　　评估板EVAL-SSM3582Z材料清单: