Boosted class-D audio amplifier with SpeakerBoost protection algorithm and dynamic range compressor TFA9895_SDS
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TFA9895 Boosted class-D audio amplifier with speaker boost protection and multiband dynamic range compressor Rev. 1 — 23 October 2013 Product short data sheet 1. General description The TFA9895 is a high efficiency class-D audio amplifier with a sophisticated speaker boost protection algorithm that features multi-band compression. It can deliver 2.65 W (RMS; THD = 1 %) output power into a 4 speaker at a battery voltage of 3.6 V. The internal boost converter raises the supply voltage to 5.3 V, providing ample headroom for major improvements in sound quality. A safe working environment is provided for the speaker under all operating conditions. The TFA9895 maximizes acoustic output while ensuring diaphragm displacement and voice coil temperature do not exceed their rated limits. This function is based on a speaker box model that operates in all loudspeaker environments (e.g. free air, closed box or vented box). Furthermore, advanced signal processing ensures that the quality of the audio signal is never degraded by unwanted clipping or distortion in the amplifier or speaker. Unlike competing solutions, the adaptive sound maximizer algorithm uses feedback to accurately calculate both the temperature and the excursion, allowing the TFA9895 to adapt to changes in the acoustic environment. Internal intelligent DC-to-DC conversion boosts the supply rail to provide additional headroom and power output. The supply voltage is only raised when necessary. This precaution maximizes the output power of the class-D audio amplifier while limiting quiescent power consumption. The multi-band processing improves audio quality and apparent volume by allowing the gain to remain stable in most of the signal while the protection reacts to only those portions that would be unsafe. The TFA9895 also adds a high-frequency noise gate that improves the sound of poor-quality audio sources. The TFA9895 also incorporates advanced battery protection. By limiting the supply current when the battery voltage is low, it prevents the audio system drawing excessive load currents from the battery, which could cause a system undervoltage. The advanced processor minimizes the impact of a falling battery voltage on the audio quality by preventing distortion as the battery discharges. The device features low RF susceptibility because it has a digital input interface that is insensitive to clock jitter. The second order closed loop architecture used in a class-D audio amplifier provides excellent audio performance and high supply voltage ripple rejection. The audio input interface is I2S and the control settings are communicated via an I2C-bus interface. The TFA9895 is available in a 29-bump WLCSP (Wafer Level Chip-Size Package) with a 400 m pitch.

Boosted class-D audio amplifier with speaker boost protection 2. Features and benefits Sophisticated speaker-boost and protection algorithm that maximizes speaker performance while protecting the speaker: Fully embedded software, no additional license fee or porting required Total integrated solution that includes DSP, amplifier, DC-to-DC, sensing and more. Adaptive excursion control guarantees that the speaker membrane excursion never exceeds its rated limit Multiband dynamic range compressor (DRC) allows independent control of up to three frequency bands Real-time temperature protection -...

Boosted class-D audio amplifier with speaker boost protection Portable Navigation Devices (PND) Notebooks/Netbooks MP3 players and portable media players 4. Quick reference data Table 1. Quick reference data battery supply voltage digital supply voltage battery supply current on pin VBAT and in DC-to-DC converter coil; Operating modes with load; DC-to-DC converter in Adaptive boost mode (no input signal) on pin VBAT and in DC-to-DC converter coil; Power-down mode on pin VDDD; Operating modes; speaker boost protection activated on pin VDDD; Operating modes; CoolFlux DSP bypassed on pin VDDD;...

without pilot tone TEMP SENSE VBAT SENSE current sensing

Boosted class-D audio amplifier with speaker boost protection 7. Pinning information 7.1 Pinning 1 bump A1 index area bump A1 index area Bump configuration Product short data sheet Bump mapping All information provided in this document is subject to legal disclaimers.

Boosted class-D audio amplifier with speaker boost protection digital audio data input 2 digital audio data output digital audio data input 1 digital audio data input 3 address select input 1 address select input 2 inverting output digital audio word select input 2 digital audio word select input 1 test signal input 3; for test purposes only, connect to PCB ground power supply voltage power ground digital audio bit clock input 2 digital audio bit clock input 1 test signal input 4; for test purposes only, connect to PCB ground test signal input 1; for test purposes only, connect to VBST...

Boosted class-D audio amplifier with speaker boost protection 8. Functional description The TFA9895 is a highly efficient mono Bridge Tied Load (BTL) class-D audio amplifier with a sophisticated speaker boost protection algorithm. Figure 1 is a block diagram of the TFA9895. The device contains three I2S input interfaces and one I2S output interface. One of I2S inputs DATAI1 and DATAI2 can be selected as the audio input stream. The third I2S input, DATAI3, is provided to support stereo applications and the I2S pass-through option. The pass-through option is provided to allow an I2S output...

Boosted class-D audio amplifier with speaker boost protection The adaptive DC-to-DC converter boosts the battery supply voltage in line with the output of the speaker boost protection algorithm. It switches to Follower mode (VBST = VBAT; no boost) when the audio output voltage is lower than the battery voltage. 8.1 Protection mechanisms The following protection circuits are included in the TFA9895: OverTemperature Protection (OTP) OverVoltage Protection (OVP) UnderVoltage Protection (UVP) OverCurrent Protection (OCP) Invalid Data Protection (IDP) The reaction of the device to fault...