Class D speaker amplifiers are compact for voice-activated devices
Claimed to deliver the highest efficiency in a compact, cost-effective package, the MAX98357 and MAX98358 are digital input, Class D audio power amplifiers from Maxim Integrated Products.
They can be used for a variety of applications to provide Class AB audio performance with Class D efficiency for superior audio quality, says Maxim.
The MAX98357 and MAX98358 Class D efficient amplifiers deliver 3.2W of Class AB audio performance. The MAX98357 pulse-code modulation (PCM) and MAX98358 pulse-density modulation (PDM) speaker amplifiers reduce overall solution size by virtue of Maxim’s pin-out. The number of required components has also been reduced, compared to typical analogue amplifier designs, says the company.
The amplifiers have the highest dynamic range in its product category, says Maxim, at 103.5dB, and best-in-class total harmonic distortion (THD) noise of 0.013 per cent. The click-pop performance is -66dBV out of shutdown, achieved via extensive click-pop reduction circuitry
A digital input is included for noise immunity, along with highest jitter tolerance (at least 8dB better than competitive solutions, claims Maxim). They are also claimed to offer “excellent electromagnetic interference (EMI) performance” and allow the use of longer traces to the speakers without added external filtering. According to the company, they also offer the highest Class D efficiency in the industry.
To simplify design, the amplifier only requires users to connect a single power supply and feed the bit clock (BCLK) and left-right clock (LRCLK) of both the MAX98357 and MAX98358, without needing a master clock (MCLK). The amplifiers further simplify designs by auto-configuring for up to 35 clocking configurations and 128 digital audio formats.
Automatic configuration eliminates complicated I²C programming as there is no longer a need to rewrite base code to configure a design just to add audio functionality, points out Maxim. The company believes that as more applications (such as smart speakers) will require multi-directional/channel audio, the need for amplifiers like the MAX98357 and MAX98358 that can be easily daisy-chained to support speaker arrays (up to eight channels supported by time division multiplex or TDM) will continue to grow.
