TS4974_07 STMICROELECTRONICS [STMicroelectronics], TS4974_07 Datasheet - Page 18

• Manufacturer Part Number: TS4974_07
• Description: 1W differential audio power amplifier with up/down digital volume control pins
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

Application information
18/25
and the maximum value is obtained when:
and its value is:
Equation 3
Note:
The efficiency is the ratio between the output power and the power supply:
Equation 4
The maximum theoretical value is reached when V
The maximum die temperature allowable for the TS4974 is 125°C. However, in case of
overheating, a thermal shutdown set to 150° C, puts the TS4974 in standby until the
temperature of the die is reduced by about 5° C.
To calculate the maximum ambient temperature T
●
●
●
Example: V
Using the power dissipation formula given above in
T
Equation 5
Therefore, the maximum allowable value for T
amb
Power supply voltage value, V
Load resistor value, R
The package type, R
P
T
is calculated as follows:
amb
dissmax
This maximum value is only dependent on the power supply voltage and load
values.
= 125-80x0.633 = 74.3°C
CC
= 633mW
=5 V, R
L
=8 Ω, R
THJA
L
T
amb
THJA
=
CC
Pdiss
flip-chip=80° C/W (125 mm
125° C R
η =
η =
max
------------------ - =
P
∂Pdiss
-------------------- - = 0
P
supply
π
---- - = 78.5%
4
∂P
=
–
out
2
amb
out
π
Vcc
TJHA
2
R
L
amb
2
is:
--------------------
πV
peak
4V
(
Equation 3
×
W
peak
)
CC
allowable, you need to know:
P
dissmax
= V
CC
, so:
this gives a result of:
2
copper heatsink).
TS4974