With users worldwide listening to stereo music, streaming video and gaming on smartphones and portable devices, the new Cirrus Logic CS35L41 smart power amplifier delivers enriched audio clarity and loudness with advanced power management, all in a small package – nearly half the size of other leading DSP smart amps. By tackling the complex engineering challenges inherent in mobile stereo audio design, Cirrus Logic enables OEMs of smartphone and battery-powered portable devices to introduce a markedly improved audio listening experience for both mono and stereo applications, while conserving battery life.
The Cirrus Logic CS35L41 11-volt boosted Class D audio amplifier with DSP, complemented with Cirrus Logic’s SoundClear Playback software, improves audio quality and increases the loudness of smartphone speaker output while protecting the speaker using both hardware and software techniques. Its advanced battery management system and predictive algorithms adapt to changing audio, speaker and battery conditions to minimize power consumption and battery current, without sacrificing audio performance. This new smart power amplifier also uses 55 nm process technology, the most advanced for this class of amplifiers, resulting in a tiny, 5.64 mm2 space-saving WLCS package. This is important to OEMs who want to include a two-speaker design, as well as pack in as many new features and functions as possible.
According to a SAR Audio Signal Chain IC forecast database from Q4 2018, market shipments for audio amplifiers have grown 3x from 2010 to 2018 due to the increasing shipments of audio playing devices, and also the increasing number of channels per device. “Amplifier shipment growth in the smart phone market is due not only to an increase in stereo sound in high-end phones but also the mid-tier market, defined as phones priced between $200 and $500,” says SAR Insight principal analyst, Peter Cooney. “We anticipate this growth to continue with an estimated increase from the 500 million amplifiers shipped into mid-tier phones in 2017, to almost 700 million by 2022.”
“More and more consumers are turning to their smartphone as a primary device for video streaming, gaming and listening to music – including using speakerphone or loudspeaker mode,” adds Carl Alberty, vice president of Marketing, Cirrus Logic. “The sound quality from a phone using the CS35L41 is so impressive that you can leave your portable speaker behind and simply carry one device to enjoy media anywhere you go without compromise.”
The core of the Cirrus Logic CS35L41 features a 5.3-watt digital input, mono Class D amplifier with the lowest noise and idle power consumption in its class. An integrated 11-volt Class H DC-DC converter boosts the supply voltage and maintains higher efficiency than other audio power amplifiers relying on Class G boost regulators. By adaptively tracking the audio level, the Class H boost converter helps improve system efficiency, minimizes power dissipation and preserves battery life.
Cirrus Logic’s SoundClear Playback software provides the ability to fine tune audio to the specific micro speaker being used in the mobile system. Equalization, compression and psychoacoustic enhancement algorithms improve sound clarity and increase loudness. Playback filtering compensates for the unique frequency response of the speaker, while eliminating pre-ringing found in conventional linear phase filters. This enables audio engineers to get the most out of small speakers and improve the gaming and video streaming audio experience for mobile device users.
The Cirrus Logic CS35L41 preserves battery life using an advanced battery management system, in addition to its Class H boost and super low 6.7-milliwatt (mW) quiescent current. By predictively managing the demand on the battery, the amplifier is able to maintain maximum loudness and audio quality, while protecting the battery by minimizing battery current draw and eliminating unexpected “brown out” conditions that shut down the phone.
The CS35L41 is currently shipping in production volumes. The company also offers tuning tools that help enable not only top-tier smartphone and portable device OEMs to introduce higher quality mono and stereo audio, but mid- and lower cost designs as well.