Datasheet

TPA0202
2-W STEREO AUDIO POWER AMPLIFIER
SLOS205B – FEBRUARY 1998 – REVISED DECEMBER 2000
36
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
APPLICATION INFORMATION
Input MUX operation
Working in concert with the SE/BTL feature, the HP/LINE MUX feature gives the audio designer the flexibility
of a multichip design in a single IC (see Figure 69). The primary function of the MUX is to allow different gain
settings for BTL versus SE mode. Speakers typically require approximately a factor of 10 more gain for similar
volume listening levels as compared to headphones. To achieve headphone and speaker listening parity, the
resistor values would need to be set as follows:
(15)
SE Gain
(HP)
R
F(HP)
R
I(HP)
If, for example R
I(HP)
= 10 kΩ and R
F(HP)
= 10 kΩ then SE Gain
(HP)
= –1
(16)
BTL Gain
(LINE)
2
R
F(LINE)
R
I(LINE)
If, for example R
I(LINE)
= 10 kΩ and R
F(LINE)
= 50 kΩ then BTL Gain
(LINE)
= –10
ROUT+
ROUT–
C
IRLINE
R
IRLINE
15
22
C
IRHP
R
IRHP
R
FRHP
MUX
RLINE IN
RHP IN
SE/BTL
HP/LINE
V
DD
16
14
+
–
Left Channel
20
21
Right Channel
MID
R
FRLINE
0.1 µF
Figure 69. TPA0202 Example Input MUX Circuit
Another advantage of using the MUX feature is setting the gain of the headphone channel to –1. This provides
the optimum distortion performance into the headphones where clear sound is more important. Refer to the
SE/BTL
operation section for a description of the headphone jack control circuit.