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TPA3136D2, TPA3136AD2

SLOS938F – MAY 2016 – REVISED JANUARY 2020

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11 Power Supply Recommendations

11.1 Power Supply Decoupling, CS

The TPA3136D2, TPA3136AD2 device is a high-performance CMOS audio amplifier that requires adequate

power supply decoupling to ensure that the output total harmonic distortion (THD) is as low as possible. Power

supply decoupling also prevents oscillations for long lead lengths between the amplifier and the speaker.

Optimum decoupling is achieved by using a network of capacitors of different types that target specific types of

noise on the power supply leads. For higher frequency transients due to parasitic circuit elements such as bond

wire and copper trace inductances as well as lead frame capacitance, a good quality low equivalent-series-

resistance (ESR) ceramic capacitor of value between 220 pF and 1000 pF works well. This capacitor should be

placed as close to the device PVCC pins and system ground (either GND pins or thermal pad) as possible. For

mid-frequency noise due to filter resonances or PWM switching transients as well as digital hash on the line,

another good quality capacitor typically 0.1 μF to 1 µF placed as close as possible to the device PVCC leads

works best. For filtering lower frequency noise signals, a larger aluminum electrolytic capacitor of 100 μF or

greater placed near the audio power amplifier is recommended. The 100-μF capacitor also serves as a local

storage capacitor for supplying current during large signal transients on the amplifier outputs. The PVCC pins

provide the power to the output transistors, so a 100-µF or larger capacitor should be placed on each PVCC pin.

A 1-µF capacitor on the AVCC pin is adequate. Also, a small decoupling resistor between AVCC and PVCC can

be used to keep high frequency class-D noise from entering the linear input amplifiers.