Datasheet

TPA0211
2-W MONO AUDIO POWER AMPLIFIER
SLOS275D – JANUARY 2000 – REVISED NOVEMBER 2002
19
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
APPLICATION INFORMATION
crest factor and thermal considerations (continued)
To calculate maximum ambient temperatures, first consider that the numbers from the dissipation graphs are
per channel so the dissipated power needs to be doubled for two channel operation. Given Θ
JA
, the maximum
allowable junction temperature, and the total internal dissipation, the maximum ambient temperature can be
calculated with the following equation. The maximum recommended junction temperature for the TPA0211 is
150°C. The internal dissipation figures are taken from the Power Dissipation vs Output Power graphs.
T
A
Max + T
J
Max * Θ
JA
P
D
+ 150 * 58.48
(
0.8 2
)
+ 56°C
(
15-dB crest factor
)
(15)
NOTE:
Internal dissipation of 0.8 W is estimated for a 2-W system with 15-dB crest factor per channel.
Table 3 shows that for some applications no airflow is required to keep junction temperatures in the specified
range. The TPA0211 is designed with thermal protection that turns the device off when the junction temperature
surpasses 150°C to prevent damage to the IC. Table 3 was calculated for maximum listening volume without
distortion. When the output level is reduced the numbers in the table change significantly. Also, using 8-Ω
speakers dramatically increases the thermal performance by increasing amplifier efficiency.
SE/BTL (stereo/mono) operation
The ability of the TPA0211 to easily switch between mono BTL and stereo SE modes is one of its most important
cost saving features. This feature eliminates the requirement for an additional headphone amplifier in
applications where an internal speaker is driven in BTL mode but an external headphone must be
accommodated. When SE/BTL
is held high for SE mode, the V
O–
output goes into a high impedance state while
the V
O+
output operates normally. When SE/BTL is held low, the V
O–
output operates normally, placing the
amplifier in BTL mode.