Maxim adds Digital Input Amps
September 2012, in a product briefing with Maxim, we discussed their new all digital Class D amplifier that is targeted at mobile, medical, industrial and automotive infotainment marketplaces. Unlike the traditional analog input Class D audio amplifiers, the digital input design can take the data stream directly from the controllers and automatically detects the input clock rate for the data and also adjusts to the bit rate and depth (16, 24, or 32 bit) and sampling rate from 8khZ-96kHz
These devices, the MAX98355 (PCM version) & MAX98356 (PDM version) feature a low THD+N of 0.013% at 1KHz and 99dB dynamic range. This THD and the associated low jitter does not significantly shift over the full power range of 0.5W into an 8ohm load. The design supports a single supply operation from 2.5v-5.5v with a very high efficiency.
MAxim MAX98355-6 Digital Class D Audio Amplifier
One of the key fearrues is that these specifications hold true with predictable shift for both thermal performance in the extended range operation (-40C to +85C) and up through the full 20Khz signal range. Class D amplifiers have traditionally either consumed high power to support the low jitter high speed clocks or had increasing THD and phase shift at the higher frequencies. The use of the digital inputs allows for simplified audio control through the elimination of the analog input pass band filters and the high Q clock rate notch filtes directly in the signal path.
These devices are sampling now and available for production in 2012, are the same size as a traditional analog Class D audio amplifier, but provides direct digital ”plug and play” type of interface. As an industrial operating range part, it is well suited to adding audio to most automation and instrumentation systems so they can easily be brought to be multi-media compatible.
