Application Information

TS4851

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and the maximum value is obtained when:

and its value is:

Note: This maximum value is depends only on power supply voltage and load values.

The efficiency is the ratio between the output power and the power supply:

The maximum theoretical value is reached when Vpeak = Vcc, so:

The TS4851 has three independent power amplifiers. Each amplifier produces heat due to its power

dissipation. Therefore, the maximum die temperature is the sum of each amplifier’s maximum power

dissipation. It is calculated as follows:

The following graph (Figure 60) shows an example of the previous formula, with Vcc set to +5V,

Figure 60: Example of total power dissipation vs. speaker and headphone output power

∂Pdiss

---------------------- = 0

)

W

(

R

Vcc

2

max

Pdiss

L

2

2

π

=

η =

Psup pl y

------------------------ = π

-----------------------

π

4

----- = 78.5%

[]

)

W

(

P

2

P

R

P

2

R

P

V

2

2

TotalP

HEAD

OUT

SPEAKER

OUT

HEAD

L

HEAD

OUT

SPEAKER

L

SPEAKER

OUT

CC

diss

+

−

⎥

⎥

⎦

⎤

⎢

⎢

⎣

⎡

+

π

=