MOSA

MS6853

Mono 1.9W / Stereo 300mW Power Amplifier

REV 6

10/14

www.mosanalog.com

SE mode and BTL mode operation

As shown in block diagram and Fig.1, in the SE mode, the MS6853 operates as a high current output dual op amp.

shut down to a high output impedance state.

In BTL mode, A3 is shutdown to a high impedance state. The audio signal from the R-IN pin is directed to the inverting

used to drive the mono bridged-tied load.

HP-IN operation

The ability of the MS6853 is easily switched between mono BTL and stereo SE modes. The mode is switched by

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.

HP-IN pin is a hysteresis control input, the hysteresis range is from 0.65VDD to 0.75VDD. In the case of 5V VDD for

MS6853 (the hysteresis voltage for HP-IN is from 3.25V to 3.75V) and 3V VDD for the controlling device, such as

MCU, a simple level shift circuit is needed, as shown below.

100k

pMOS

MCU

V

5V

MS6853

V

HP-IN

Thermal pad considerations

The thermal pad must be connected to ground. The package with thermal pad of the MS6853 requires special attention

on thermal design. The thermal pad on the bottom of the MS6853 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.