Analog Devices Inc. SSM2375 High-Efficiency Class-D Audio Amplifiers

Analog Devices SSM2375 Class-D Audio Amplifiers are fully integrated, high-efficiency Class-D audio amplifiers designed to maximize performance for mobile phone applications. Operating from a single 2.5V to 5.5V supply, Analog Devices SSM2375 Audio Amplifiers feature an application circuit that requires a minimum number of external components. SSM2375 can generate 3W of continuous output power with less than 1% THD + N driving a 3Ω load from a 5V supply.

SSM2375's spread spectrum pulse-density modulation (PDM) lowers EMI-radiated emissions compared to other Class-D architectures. The inherent randomized nature of spread spectrum PDM eliminates clock intermodulation (beating effect) of several amplifiers in close proximity. The design of the SSM2375 includes an optional modulation select pin for ultra-low EMI emissions mode that significantly reduces the radiated emissions at the Class-D outputs, especially above 100MHz. In ultra-low EMI emissions mode, the SSM2375 Audio Amplifiers can pass FCC Class B radiated emission testing with 50cm, unshielded speaker cable without any external filtering.

Features

Filterless Class-D amplifier with spread-spectrum Σ-Δ modulation
3W into 3Ω load and 1.4W into 8Ω load at 5V supply with <1% total harmonic distortion (THD + N)
93% efficiency at 5V, 1.4W into 8Ω speaker
>100dB signal-to-noise ratio (SNR)
80dB high PSSR at 217Hz
0dB to 12dB in dB steps flexible gain adjustment pin
80kΩ fixed input impedance