CS35L41 Boosted Class D Audio Amplifier with DSP

CS35L41 Package Size

and Footprint

CS35L41 Package Size and Footprint:

74% smaller

than nearest smart amplifier competitor

Space Saving Package

Enhanced Audio and Battery Performance

© 2018 Cirrus Logic, Inc. All rights reserved. Cirrus Logic, Cirrus, the Cirrus Logic logo design, and SoundClear are trademarks of Cirrus Logic, Inc. Other brand and product names in this document may be trademarks or service marks

of their respective owners.

Cirrus Logic, Inc.

800 West Sixth Street

Austin, Texas 78701

United States

T+1-512-851-4000

Sales Support

North America +1-800-888-5016

Asia Pacific +852 2376-0801

Japan +81-(3)-5782-8180

Europe/UK +44-(0)-131-272-7000

NOVEMBER 2018

cirrus.com

2.2884 mm

2.51 mm

3.2 mm

Figure 2 – Class G and Class H Supply Rail Voltage vs. Time

Vbat

3.6 V

Wasted Power

Cirrus Logic Class H

Boost Supply

Example Class G

Boost Supply

Figure 3 – Predictive Battery Management Performance

With Cirrus Logic Advanced

Battery Management System

With no battery management

Phone Battery Voltage

while playing stereo

audio through speakers

Vbat

3.6 V

Audio Enhancement

Cirrus Logic’s SoundClear Playback provides the ability to

fine tune the CS35L41 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 as shown in Figure 1. These algorithms

are integrated into the on-chip DSP and prevent additional

workloads from being placed on the application processor.

Battery Management

The CS35L41 preserves battery life using an advanced

battery management system in addition to its Class H

boost and extremely low quiescent current. As illustrated

in Figure 2, the Class H DC-DC converter boosts the

supply while maintaining higher efficiency than the Class

G boost regulators commonly used in other smart

amplifiers. The battery management system predictively

adapts to changing audio, speaker and battery conditions

by intelligently regulating battery current to protect the

amplifier from drawing high currents that can cause a

system brownout if managed incorrectly. Figure 3 shows

that by predictively managing the demand on the battery,

the amplifier is able to maximize loudness and audio quality

while minimizing the power impact to the mobile device.

Conventional

Linear Phase Filter

Pre-ringing of a

Conventional Linear

Phase Filter

Playback Filter

Response

Figure 1 – Playback Filtering