The TPA0242 Audio Power Amplifier Evaluation Module
Figure 3±4. TPA0242 Amplifier IC |
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L HP |
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L IN |
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L LINE |
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PC BEEP | PC BEEP | VOLUME | VOLUME |
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R LINE |
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R IN |
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R HP |
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| HP/LINE | SE/BTL |
3.2.2Inputs and Gain
Each channel has two separate signal inputs, line and headphone (HP), that are automatically selected with the output mode (SE/BTL). An input multi- plexor in the amplifier IC selects the HP inputs when the IC is in the SE output mode and the line inputs when in the BTL output mode.
Line and headphone inputs share common positive inputs. If using separate line and headphone inputs, R IN and L IN should be AC grounded through a capacitor. If using differential inputs, line and headphone inputs must be the same.
A third input, PC BEEP, is common to both channels. The TPA0242 IC monitors this input when operating in both the active and shutdown modes and automatically switches to this input when a signal is sensed. In computer applications, for example, this allows the normal audio signal (music, sounds, etc.) to be interrupted when there is a need to output a computer beep. When the beep signal ends, the IC switches back to the previous mode.
The PC BEEP input gain is approximately 1/4 V/V, and requires an input signal greater than 1 V
Details
