The TFA9890A is a high efficiency class-D audio amplifier with a sophisticated speakerboost and protection algorithm. It can deliver 7.2 W peak output power into an 8 Ωspeaker at a supply voltage of 3.6 V. The internal boost converter raises the supplyvoltage to 9.5 V, providing ample headroom for major improvements in sound quality.

A safe working environment is provided for the speaker under all operating conditions.The TFA9890A maximizes acoustic output while ensuring diaphragm displacement andvoice coil temperature do not exceed their rated limits. This function is based on aspeaker box model that operates in all loudspeaker environments (e.g. free air, closed boxor vented box). Furthermore, advanced signal processing ensures that the quality of theaudio signal is never degraded by unwanted clipping or distortion in the amplifier orspeaker.

Unlike competing solutions, the adaptive sound maximizer algorithm uses feedback toaccurately calculate both the temperature and the excursion, allowing the TFA9890A toadapt to changes in the acoustic environment.

Internal intelligent DC-to-DC conversion boosts the supply rail to provide additionalheadroom and power output. The supply voltage is only raised when necessary. Thismaximizes the output power of the class-D audio amplifier while limiting quiescent powerconsumption.

The TFA9890A also incorporates advanced battery protection. By limiting the supplycurrent when the battery voltage is low, it prevents the audio system from drawingexcessive load currents from the battery, which could cause a system undervoltage. Theadvanced processor minimizes the impact of a falling battery voltage on the audio qualityby preventing distortion as the battery discharges.

The device features low RF susceptibility because it has a digital input interface that isinsensitive to clock jitter. The second order closed loop architecture used in a class-Daudio amplifier provides excellent audio performance and high supply voltage ripplerejection. The audio input interface is I2S and the control settings are communicated viaan I2C-bus interface.

The device also provides the speaker with robust protection against ESD damage. In atypical application, no additional components are needed to withstand a 15 kV dischargeon the speaker.

The TFA9890A is available in a 49-bump WLCSP (Wafer Level Chip-Size Package) with a400 μm pitch.

• Sophisticated speaker-boost and protection algorithm that maximizes speakerperformance 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 neverexceeds its rated limit
• Real-time temperature protection - direct measurement ensures that voice coiltemperature never exceeds its rated limit
• Environmentally aware - automatically adapts speaker parameters to acoustic andthermal changes including compensation for speaker-box leakage
• Speaker error detection (detects faulty speakers and enclosures)
• Output power: 3.6 W (RMS) into 8 Ω at 3.6 V supply voltage (THD = 1 %)
• Clip avoidance - DSP algorithm prevents clipping even with sagging supply voltage
• Bandwidth extension option to increase low frequency response
• Compatible with standard Acoustic Echo Cancellers (AECs)
• High efficiency and low power dissipation
• Wide supply voltage range (fully operational from 2.7 V to 5.5 V)
• Two I2S inputs to support two audio sources
• I2C-bus control interface (400 kHz)
• Dedicated speech mode with speech activity detector
• Speaker current and voltage monitoring (via the I2S-bus) for Acoustic EchoCancellation (AEC) at the host
• Fully short-circuit proof across the load and to the supply lines
• Sample frequencies from 8 kHz to 48 kHz supported
• 3 bit clock/word select ratios supported (32x, 48x, 64x)
• Option to route I2S input direct to I2S output to allow a second I2S output slave deviceto be used in combination with the TFA9890A
• TDM interface supported (with limited functionality)
• Volume control
• Low RF susceptibility
• Input clock jitter insensitive interface
• Thermally protected
• 15 kV system-level ESD protection without external components
• ‘Pop noise' free at all mode transitions

• Mobile phones
• Tablets
• Portable Navigation Devices (PND)
• Notebooks/Netbooks
• MP3 players and portable media players
• Small audio systems