TFA9872_SDS
High Efficiency Class-D Audio Amplifier with Speaker-as-
Microphone
Rev. 1 — 12 April 2017
Product short data sheet
COMPANY PUBLIC
1 General description
The TFA9872 is a 9.5 V boosted class-D audio amplifier featuring Speaker-as-
Microphone (SaM) and Receiver-as-Microphone (RaM) modes. It can deliver up to
10.0 W peak output power into an 8 Ω speaker and up to 11.8 W peak output power into
a 6 Ω speaker, at a supply voltage of 4.0 V. The internal adaptive DC-to-DC converter
raises the supply voltage to 9.5 V, providing ample headroom for major improvements in
sound quality.
Internal adaptive DC-to-DC conversion boosts the supply rail to provide additional
headroom and power output. The supply voltage is only raised when necessary,
maximizing the output power of the class-D audio amplifier while limiting quiescent power
consumption.
The device can be configured to drive either a hands-free speaker (4 Ω to 8 Ω) for audio
playback, or a receiver speaker (32 Ω) for handset playback, allowing it to be embedded
in platforms that support either or both options. The maximum output power, gain, and
noise levels are lower in the Handset Call use case than in the Hands-free Call use case.
The SaM feature allows the speaker to be used as an additional microphone when
not configured for audio playback. This function performs best in high sound pressure
environments (like concert recording or wind noise calls) and is targeted at such use
cases.
The TFA9872 also incorporates battery protection. By limiting the supply current when
the battery voltage is low, the device is prevented from switching off unexpectedly due to
excessive load currents (excessive load currents can lead to a system undervoltage).
Because it has a digital input interface that is insensitive to clock jitter, the TFA9872
features low RF susceptibility. 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 TFA9872 is available in a 42-bump WLCSP (Wafer Level Chip-Size Package) with a
400 mm pitch.