MOSA

MS6863

Dual 2W Power Amplifiers with Stereo Headphone

REV 1

10

www.mosanalog.com

APPLICATION INFORMATION

Application example

This example is compatible for LM4863.

V

INA

V

INB

MS6863

R

L

8Ω

100uF

1k

100uF

1k

Headphone Jack

R

L

8Ω

HP-IN

16

18

5

3

15

20

1uF

20k

R

IN

20K

R

F

20K

R

F

6

-INA

-INB

-OUTB

+OUTB

-OUTA

+OUTA

1uF

V

DD

GND

VDD

2,7,19

4,17

1

SD

MCU

0.33uF

13

14

8

+INA

BYPASS

+INB

R

IN

1uF

20k

100k

V

DD

Fig.1

A audio amplifier application circuit.

SE mode and BTL mode operation

As shown in block diagram and Fig.1, in the SE mode, the MS6863 operates as high current output dual operational

amplifiers A2 and B2 are shutdown, then the amplifiers will be a high output impedance state.

In BTL mode, the audio signal from the -INA (-INB) pin is directed to the inverting input of A1(B1). The A2(B2) is

then used to drive the bridged-tied load.

HP-IN operation

The ability of the MS6863 is easily switched between dual BTL and stereo SE modes. The mode is switched by the

headphone control pin, HP-IN. A logic-high activates the SE mode when a set of headphone plugged into the system,

on the other hand, a logical-low to HP-IN activates the BTL mode when no headphones.

SHUTDOWN mode

SD places the entire device in shutdown mode when held high.

Thermal pad considerations

The thermal pad must be connected to ground. The package with thermal pad of the MS6863 requires the special

attention on thermal design. The thermal pad on the bottom of the MS6863 should be soldered down to a copper pad on

the circuit board. Heat can be conducted away from the thermal pad through the copper plane to ambient. If the copper

plane is not on the top surface of the circuit board, 9 vias of 13 mil or smaller in diameter should be used to thermally

couple the thermal pad to the bottom plane. For good thermal conduction, the vias must be plated through and solder

filled.