Datasheet
TPA0202
2-W STEREO AUDIO POWER AMPLIFIER
SLOS205B – FEBRUARY 1998 – REVISED DECEMBER 2000
35
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
APPLICATION INFORMATION
SE/BTL
operation
The ability of the TPA0202 to easily switch between BTL and SE modes is one of its most important cost saving
features. This feature eliminates the requirement for an additional headphone amplifier in applications where
internal stereo speakers are driven in BTL mode but external headphone or speakers must be accommodated.
Internal to the TPA0202, two separate amplifiers drive OUT+ and OUT–. The SE/BTL
input (terminal 14)
controls the operation of the follower amplifier that drives LOUT– and ROUT– (terminals 10 and 15). When
SE/BTL
is held low, the amplifier is on and the TPA0202 is in the BTL mode. When SE/BTL is held high, the OUT–
amplifiers are in a high output impedance state, which configures the TPA0202 as an SE driver from LOUT+
and ROUT+ (terminals 3 and 22). I
DD
is reduced by approximately one-half in SE mode. Control of the SE/BTL
input can be from a logic-level CMOS source or, more typically, from a resistor divider network as shown in
Figure 68.
MUX
RLINE IN
RHP IN
+
–
Bypass
SE/BTL
HP/LINE
R
m2
100 kΩ
R
m1
100 kΩ
V
DD
C
OUTR
16
14
R
m3
1 kΩ
+
–
ROUT–
15
ROUT+ 22
Left
Channel
20
21
0.1 µF
Figure 68. TPA0202 Resistor Divider Network Circuit
Using a readily available 1/8-in. (3.5 mm) stereo headphone jack, the control switch is closed when no plug is
inserted. When closed the 100-kΩ/1-kΩ divider pulls the SE/BTL
input low. When a plug is inserted, the 1-kΩ
resistor is disconnected and the SE/BTL
input is pulled high. When the input goes high, the OUT– amplifier is
shutdown causing the speaker to mute (virtually open-circuits the speaker). The OUT+ amplifier then drives
through the output capacitor (C
O
) into the headphone jack.
As shown in the full feature application (Figure 63), the input MUX control can be tied to the SE/BTL
input. The
benefits of doing this are described in the following input MUX operation section.