The TFA9897 is a high efficiency class-D audio amplifier with a sophisticatedspeaker-boost protection algorithm. It can deliver 1.2 W (RMS; THD = 1 %) output powerinto an 8 Ω speaker at a battery voltage of 3.6 V. The internal boost converter raises thesupply voltage to 5.3 V, providing ample headroom for major improvements in soundquality.

A safe working environment is provided for the speaker under all operating conditions.The TFA9897 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 audio signal isalways of optimum quality.

The adaptive sound maximizer algorithm uses feedback to accurately calculate both thetemperature and the excursion, allowing the TFA9897 to adapt to changes in the acousticenvironment.

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

The TFA9897 also incorporates advanced battery protection. By limiting the supplycurrent when the battery voltage is low, it prevents the audio system drawing excessiveload currents from the battery (excessive load currents could cause a systemundervoltage). The advanced processor minimizes the impact of a falling battery voltageon the audio quality by 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 TDM and can be I2S configured. Control settings arecommunicated via an I2C-bus interface.

The TFA9897 is available in a 30-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
• Output power: 1.2 W (RMS) into 8 Ω at 3.6 V supply voltage (THD = 1 %)
• Low noise Receiver mode
• Clip avoidance - DSP algorithm prevents clipping even with sagging supply voltage
• Bandwidth extension option to increase low frequency response
• Intelligent DC-to-DC converter maximizes audio headroom from any supply level andlimits current consumption at low battery voltages
• Compatible with standard Acoustic Echo Cancellers (AECs)
• High efficiency and low-power dissipation
• Wide supply voltage range (fully operational from 2.5 V to 5.5 V)
• TDM audio interface configurable from 2 slots (I2S) up to 16 slots
• I2C-bus control interface (400 kHz)
• Dedicated speech mode with speech activity detector
• Speaker current and voltage monitoring (via the TDM-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 up to 48 kHz supported
• Option to route TDM input direct to TDM output to allow a second TDM input slavedevice to be used in combination with the TFA9897
• Volume control
• Low RF susceptibility
• Input clock jitter insensitive interface
• Thermally protected
• Low ‘pop noise' at all mode transitions

• Mobile phones
• Tablets
• Portable gaming devices
• Portable Navigation Devices (PND)
• Notebooks/Netbooks
• MP3 players and portable media players