ADI SSM2380 2x2W D类立体声音频放大方案

ADI公司的SSM2380是带ALC+I2C的无滤波器2x2W D类立体声音频放大器,单电源2.5V到5.5V工作,在5.0V电源时能向4欧姆负载提供2W连续输出功率,而THD+N小于1%,效率为93%,信噪比大于100dB.SSM2380主要应用在手机,MP3播放器,手提电子设备.本文介绍SSM2380主要特性, 功能方框图, I2C 模式, ALC 模式和增益模式的典型应用电路图及其配置图.
SSM2380: 2x2W Filterless Class-D Stereo Audio Amplifier with ALC + I2C
The SSM2380 is a fully integrated, high efficiency, stereo Class-D audio amplifier. It is designed to maximize performance for mobile phone applications. The application circuit requires a minimum of external components and operates from a single 2.5 V to 5.5 V supply. It is capable of delivering 2 W of continuous output power with <1% THD + N driving a 4 Ω load from a 5.0 V supply.
The SSM2380 features a highly flexible I2C interface with many useful settings. Using the I2C control interface, the gain of SSM2380 can be selected from 1dB to 24 dB + Mute in 47 steps with no external components. Other features accessed from the I2C interface are: Independent L/R channel shutdown, Variable ultra-low EMI emission control mode, Automatic Level Control (ALC) for high quality speaker protection, and Stereo-to-Mono mixing operation.
The SSM2380 features a high efficiency, low noise modulation scheme that requires no external LC output filters. The modulation continues to provide high efficiency even at low output power. It operates with 93% efficiency at 1.4 W into 8 Ω or 85% efficiency at 2W into 4 Ω from a 5.0 V supply and has an SNR of >100 dB. Spread-spectrum pulse density modulation is used to provide lower EMI-radiated emissions compared with other Class-D architectures. An added benefit of spread-spectrum Σ-Δ modulation is that no synchronization (SYNC) is needed when using multiple Class-D amplifiers. For applications that require long speaker cables (>10cm), the SSM2380 includes a user selectable ultra-low EMI emission mode that eliminates the need for EMI filters a...