2.2 H

m

2.2 F – 10 F

m

m

6.8 F – 22 F

m

m

IN-

IN+

GAIN

ENB

END

GND

VDD

SW PVOUT

PVDD

OUT+

OUT-

TPA2015D1

Differential

Audio Inputs

Connected to Supply

Gain Control

Boost Enable

Class-D Enable

AGC

AGC Control

47 nF

100 W

Figure 9-6. Reducing Out-of-Band DAC Noise With External Input Filter

9.3.5 Filter Free Operation and Ferrite Bead Filters

The TPA2015D1 is designed to minimize RF emissions. For more information about RF emissions and filtering

requirements, see SLOA145.

9.3.6 Speaker Load Limitation

Speakers are non-linear loads with varying impedance (magnitude and phase) over the audio frequency. A

portion of speaker load current can flow back into the boost converter output via the Class-D output H-bridge

high-side device. This is dependent on the speaker's phase change over frequency, and the audio signal

amplitude and frequency content.

Most portable speakers have limited phase change at the resonant frequency, typically no more than 40 or

50 degrees. To avoid excess flow-back current, use speakers with limited phase change. Otherwise, flow-back

current could exceed the 10 mA rating of the boost converter voltage clamp and drive the PVOUT voltage above

the absolute maximum recommended operational voltage.

Confirm proper operation by connecting the speaker to the TPA2015D1 and driving it at maximum output swing.

Observe the PVOUT voltage with an oscilloscope. In the unlikely event the PVOUT voltage exceeds 6.5 V, add a

6.8 V Zener diode between PVOUT and ground to ensure the TPA2015D1 operates properly.

The amplifier has thermal overload protection and decatives if the die temperature exceeds 150°C. It

automatically reactivates once die temperature returns below 150°C. Built-in output over-current protection

deactivates the amplifier if the speaker load becomes short-circuited. The amplifier automatically restarts within

200 ms after the over-current event. Although the TPA2015D1 Class-D output can withstand a short between

OUT+ and OUT-, do not connect either output directly to GND, PVDD, or VBAT as this could damage the device.

CAUTION

Do not connect OUT+ or OUT- directly to GND, PVDD, or VBAT as this could damage the Class-D

output stage.

9.3.7 Fixed Gain Setting

The TPA2015D1 has 3 selectable fixed-gains: 6 dB, 15.5 dB, and 20 dB. Connect the GAIN pin as shown in

Table 9-2.

TPA2015D1

SLOS638C – NOVEMBER 2011 – REVISED JUNE 2022

www.ti.com

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