NXP's TFA9894D is a high efficiency 10 V boosted Class-D audio amplifier with a sophisticated SpeakerBoost and protection algorithm. It can deliver up to 5.6 W (AVG) output power into an 8 ohm speaker and up to 6.2 W (AVG) output power into a 4 ohm speaker, at a battery supply voltage of 4.0 V. The internal adaptive DC-to-DC converter raises the power supply voltage to 10 V, providing ample headroom for major improvements in sound quality.

A safe working environment is provided for the speaker under all operating conditions. The TFA9894D maximizes acoustic output while ensuring membrane displacement and voice coil temperature does not exceed their rated limits. This function is based on a speaker box model that operates in all speaker 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.

NXP's TFA9894 Block Diagram

TFA9894 Product Summary Page

TFA9894D Introduction Video

Features and Benefits

• Sophisticated SpeakerBoost and protection algorithm that maximizes speaker performance while protecting the speaker:
• Fully embedded software; no additional license fee or porting required
• Fully integrated solution, including DSP, amplifier, DC-to-DC, thermal sensing
• Environmentally aware - automatically adapts speaker parameters to acoustic and thermal changes including compensation for speaker-box leakage
• Clip avoidance - DSP algorithm prevents clipping even with sagging supply voltage
• Automatic bandwidth extension to increase low-frequency response
• TFA9894D high output power: 5.6 W (AVG) into 8 Ω at 4.0 V supply voltage (THD = 1 %, VBST = 10 V), 6.2 W (AVG) into 4 Ω at 4.0 V supply voltage (THD = 1 %, VBST = 9 V)
• Supports handset and hands-free (4 Ω to 32 Ω) speaker configurations
• High efficiency, low power dissipation, and low noise speaker driver (dynamic range > 110 dB)
• Adaptive DC-to-DC converter increases the supply voltage smoothly when switching between fixed boost and adaptive boost mode, preventing large battery supply spikes and limiting quiescent power consumption
• Wide supply voltage range (fully operational from 2.7 V to 5.5 V)
• Very low noise output (typical 14 μV with null DATA input at Fs = 48 kHz)
• I²C-bus control interface (400 kHz)
• Speaker current and voltage monitoring (via the TDM-bus), as well as DSP data output (with and without pilot tone) for AEC (acoustic echo cancellation) at the host
• Multiple sample rate supported: 16 kHz, 32 kHz, 44.1 kHz, and 48 kHz
• Easy routing support one-layer PCB design
• 3.3 V digital I/O to fit in MCU platform
• SpeakerBoost 2.0 algorithm embedded for drums and audio quality improvement
• 91% peak efficiency for 600 mW sinewave
• Exceptional power efficiency enables the highest capability and dynamic range up to 112 dB on 8 ohm speaker
• Small package size: WLCSP48: 2.51 mm x 3.55 mm x 0.525 mm