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Charge Pump Flying Capacitor and PVSS Capacitor

0.001

0.01

0.1

1

10

100

1 k

10 k

100 k

f − Frequency − Hz

C = 1

µF

C = 2.2

µF

0.1

1

10

100

0.0001

0.001

0.01

0.1

1

C = 1

µF

In Phase

180

° Out of Phase

Single Channel

0.001

0.01

0.1

1

10

100

0.001

0.01

0.1

In Phase

180

° Out of Phase

Single Channel

C = 2.2

µF

TPA4411

TPA4411M

SLOS430E – AUGUST 2004 – REVISED MARCH 2008

The charge pump flying capacitor serves to transfer charge during the generation of the negative supply voltage.

The PVSS capacitor must be at least equal to the charge pump capacitor in order to allow maximum charge

transfer. Low ESR capacitors are an ideal selection, and a value of 2.2 µF is typical. Capacitor values that are

smaller than 2.2 µF can be used, but the maximum output power is reduced and the device may not operate to

specifications. Figure 65 through Figure 75 compare the performance of the TPA4411 and TPA4411M with the

recommended 2.2-µF capacitors and 1-µF capacitors.

TOTAL HARMONIC DISTORTION

+ NOISE

vs

FREQUENCY

Figure 65.

TOTAL HARMONIC DISTORTION

TOTAL HARMONIC DISTORTION

+ NOISE

+ NOISE

vs

vs

OUTPUT POWER

OUTPUT POWER

Figure 66.

Figure 67.

Copyright © 2004–2008, Texas Instruments Incorporated

17

Product Folder Link(s): TPA4411 TPA4411M