VCC

MUTE

SHUTDOWN

C12

0.22

F

m

1

2

TPA3121D2

PVCCL1

1

SDZ

2

PVCCL2

3

MUTE

4

LIN

5

RIN

6

BYP

7

GND1

8

GND2

9

PVCCR1

10

VCLAMP

11

PVCCR2

12

PVSSR2

13

PVSSR1

14

OUTR

15

BSR

16

GAIN1

17

GAIN0

18

AVCC2

19

AVCC1

20

BSL

21

OUTL

22

PVSSL2

23

PVSSL1

24

220 W

R8

C7

0.1

F

m

C8

+

1

2

C15

0.22

F

m

C2

+

0.1

F

m

C1

C3

1.0

F

m

C4

1.0

F

m

L1

33

H

m

L2

33 mH

C17

470

F

m

C10

470

F

m

−100

−90

−80

−70

−60

−50

−40

−30

−20

−10

0

f − Frequency − Hz

G026

20

100

1k

10k

20k

VCC = 24 V

VO(ripple) = 0.2 VPP

RL = 8 Ω (SE)

Gain = 20 dB

−100

−90

−80

−70

−60

−50

−40

−30

−20

−10

0

f − Frequency − Hz

G027

20

100

1k

10k

20k

VCC = 24 V

VO(ripple) = 0.2 VPP

RL = 8 Ω (SE)

Gain = 20 dB

TPA3121D2

SLOS537B – MAY 2008 – REVISED JANUARY 2014

www.ti.com

Figure 29. PSRR Without AVCC Filter

Figure 30. PSRR With AVCC Filter

Figure 31. Application Schematic with 220-

Ω/220-μF AVCC Filter

BSN and BSP Capacitors

The half H-bridge output stages use only NMOS transistors. Therefore, they require bootstrap capacitors for the

high side of each output to turn on correctly. A 220-nF ceramic capacitor, rated for at least 25 V, must be

connected from each output to its corresponding bootstrap input. Specifically, one 220-nF capacitor must be

connected from LOUT to BSL, and one 220-nF capacitor must be connected from ROUT to BSR.

The bootstrap capacitors connected between the BSx pins and their corresponding outputs function as a floating

power supply for the high-side N-channel power MOSFET gate-drive circuitry. During each high-side switching

cycle, the bootstrap capacitors hold the gate-to-source voltage high enough to keep the high-side MOSFETs

turned on.

16

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