5

Application information

5.1

Application circuit

Figure 19. Application circuit for 6 Ω or 8 Ω speakers

L+

R+

R-

VCC

GND

L+

L-

R+

R-

TDA7498

MUTE

STBY

3V3 POWER SUPPLY

Single-Ended

*

*

*

*

*

Input

CLASS-D AMPLIFIER

*

*

*

*

Single-Ended

Input

Load = 6 ohm

For

For

FREQUENCY SHIFT

OUTPUT

INPUT

L-

*

LC FILTER COMPONENTS

Load

L1,L2,L3,L4

C20,C26

C18,C22,C24,C28

6 ohm

8 ohm

22 uH

22 uH

470 nF

680 nF

220 nF

220 nF

C5

100nF

R3

39K

L4

22uH

C1

1uF

C2

1uF

C11

1uF

C12

1uF

C8

100nF

C25

100nF

C19

100nF

C27

330pF

R6

22R

C40

220nF

C41

220nF

C21

330pF

R5

22R

C42

220nF

C43

220nF

C14

1nF

32 INPB

36 VSS

9

OUTNB

5

PGNDB

7

PVCCB

3

OUTPB

10

OUTNA

12

PVCCA

14

PGNDA

16

OUTPA

33 INNB

8

OUTNB

4

PGNDB

21 MUTE

6

PVCCB

2

OUTPB

29

SVR

11

OUTNA

1

SUB_GND

22 INPA

23

INNA

27 SGND

26

VDDS

28 DIAG

19 VDDPW

18 PGND

20 STBY

24 ROSC

31 GAIN1

35

SVCC

30

GAIN0

25 SYNCLK

17

OUTPA

15

PGNDA

34

VREF

13

PVCCA

IC1

TDA7498

R1

100k

R7

22R

C6

100nF

R4

120k

R2

33k

R8

6.8k

C26

680nF

C10

100nF

C20

680nF

J6

J5

2

1

3

S1

2

1

3

S2

C29

2.2uF

2 GND

1

OUT

3

IN

IC2

L4931CZ33

1

2

J2

J8

J7

+

C23

2200uF

50V

L3

22uH

L1

22uH

L2

22uH

J4

C30

1uF

C31

1uF

R14

100k

R15

8R

C28

220nF

R16

8R

C24

220nF

R17

8R

C18

220nF

R18

8R

C22

220nF

1

2

3

4

J3

2

4

1

3

J1

R13

47k

C13

1nF

+

C15

2.2uF

16V

+

C7

2.2uF

16V

D1

18V

C9

100nF

C4

1nF

C3

1nF

C16

10uF

10V

C17

10uF

10V

R9

180K

1

2

3

Q1

KTC3875(S)

DIAG

VCC

3V3

3V3

FS

FS

VDDS

VDDS

5.2

Mode selection

The three operating modes of the TDA7498 are set by the two inputs, STBY (pin 20) and MUTE (pin 21).

•

Standby mode: all circuits are turned off, very low current consumption.

•

Mute mode: inputs are connected to ground and the positive and negative PWM outputs are at 50% duty

cycle.

•

Play mode: the amplifiers are active.

The protection functions of the TDA7498 are enabled by pulling down the voltages of the STBY and MUTE inputs

shown in Figure 20. Standby and mute circuits. The input current of the corresponding pins must be limited to 200

µA.

Table 6. Mode settings

Mode

STBY

MUTE

Standby

L (1)

X (don’t care)

Mute

H (1)

L

Play

H

H

1. Drive levels defined in Table 5. Electrical specifications

TDA7498

Application information

DS6437 - Rev 10

page 11/22