TA1101B Datasheet, PDF (8/13 Pages) Tripath Technology Inc. – Stereo 10W (4Ω) Class-T™ Digital Audio Amplifier using Digital Power Processing™ Technology

TECHNICAL INFORMATION
Application Information
Layout Recommendations
The TA1101B is a power (high current) amplifier that operates at relatively high switching frequencies. The
outputs of the amplifier switch between the supply voltage and ground at high speeds while driving high
currents. This high-frequency digital signal is passed through an LC low-pass filter to recover the amplified
audio signal. Since the amplifier must drive the inductive LC output filter and speaker loads, the amplifier
outputs can be pulled above the supply voltage and below ground by the energy in the output inductance.
To avoid subjecting the TA1101B to potentially damaging voltage stress, it is critical to have a good printed
circuit board layout. It is recommended that Tripath’s layout and application circuit be used for all
applications and only be deviated from after careful analysis of the effects of any changes.
The figure below is the Tripath TA1101B evaluation board. Some of the most critical components on the
board are the power supply decoupling capacitors. C7 and C18 must be placed right next to pins 24 and
28 as shown. C8 and C19 must be placed right next to pins 21 and 18 as shown. These power supply
decoupling capacitors from the output stage not only help reject power supply noise, but they also absorb
voltage spikes on the VDD pins caused by overshoots of the outputs of the amplifiers. Output overshoots
include those caused by output inductor flyback during high current switching events such as shorted
outputs or driving low impedances at high levels. If the supply capacitors are not close enough to the
pins, electrical overstress to the part can occur from the voltage spikes on the VDD pins. This may result
in permanent damage or destruction to the TA1101B.
The copper slug of the TA1101B must be soldered onto the PC board. This board uses a 5 x 16 array of
0.013” vias on the copper below the TA1101 that allow the heat to conduct to 4 sq. in. of copper on the
bottom side ground plane of the PC board.
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TA1101B, Rev. 2.2, 08.17.00