Application Information

TS4984

21/29

Then, the power dissipated by each amplifier is:

and the maximum value is obtained when:

and its value is:

Note:

This maximum value is only depending on power supply voltage and load values.

The efficiency,

η, is the ratio between the output power and the power supply:

The TS4984 has two independent power amplifiers, and each amplifier produces heat due to its power

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

dissipation. It is calculated as follows:

or, stated differently:

P

di ss

P

sup pl y

P

out

–

=

W

()

P

diss

22 V

CC

π R

L

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

P

out

P

out

–

⋅

=

W

()

∂P

diss

∂P

out

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

P

dissmax

2V

cc

2

L

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

=

W

()

η =

P

out

P

supply

--------------------- =

PEAK

4V

CC

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

π

4

----- = 78.5%

Total P

diss

2P

di ssL

(W)

=

Total P

diss

42 V

CC

L

------------------------P

out

2P

out

–

=

W

()