Texas Instruments manual ±1. TPA0242 EVM BTL Volume Settings, Differential Input

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The TPA0242 Audio Power Amplifier Evaluation Module

Potentiometer R2 adjusts the gain of the internal preamp stage of the TPA0242 amplifier by adjusting the control voltage applied to the VOLUME terminal (pin

3)of the IC. Rotating the potentiometer slider clockwise decreases the applied control voltage, resulting in a higher volume. Table 3±1 shows the relationship between the control voltage applied to the VOLUME terminal and the effective amplifier gain. Headphone gain is reduced by 6 dB.

Table 3±1. TPA0242 EVM BTL Volume Settings

VOLUME (Pin 3)

BTL

VOLUME (Pin 3)

BTL

VOLUME (Pin 3)

BTL

 

 

 

 

 

 

FROM

TO

GAIN

FROM

TO

GAIN

FROM

TO

GAIN

(V)

(V)

(dB)

(V)

(V)

(dB)

(V)

(V)

(dB)

 

 

 

 

 

 

 

 

 

0

0.15

20

1.28

1.39

±2

2.52

2.63

±24

 

 

 

 

 

 

 

 

 

0.15

0.28

18

1.39

1.5

±4

2.63

2.74

±26

 

 

 

 

 

 

 

 

 

0.28

0.39

16

1.5

1.62

±6

2.74

2.86

±28

 

 

 

 

 

 

 

 

 

0.39

0.5

14

1.62

1.73

±8

2.86

2.97

±30

 

 

 

 

 

 

 

 

 

0.5

0.61

12

1.73

1.84

±10

2.97

3.08

±32

 

 

 

 

 

 

 

 

 

0.61

0.73

10

1.84

1.95

±12

3.08

3.2

±34

 

 

 

 

 

 

 

 

 

0.73

0.84

8

1.95

2.07

±14

3.2

3.31

±36

 

 

 

 

 

 

 

 

 

0.84

0.95

6

2.07

2.18

±16

3.31

3.42

±38

 

 

 

 

 

 

 

 

 

0.95

1.06

4

2.18

2.29

±18

3.42

3.54

±40

 

 

 

 

 

 

 

 

 

1.06

1.17

2

2.29

2.41

±20

3.54

5

±85

 

 

 

 

 

 

 

 

 

1.17

1.28

0

2.41

2.52

±22

 

 

 

Since the overall gain of the amplifier is set by the internal preamp stage and not by the power amplifier stage, the TPA0242 maintains the same total harmonic distortion (THD) at even the highest gain settings.

3.2.3Differential Input

The TPA0242 line inputs allow the use of a single-ended or differential audio source. The differential input stage of the amplifier cancels any noise that appears on both input lines of a channel. To use the TPA0242 EVM with a differential source, connect the positive lead of the audio source to the R LINE± (L LINE±) input and the negative lead from the audio source to the R IN+ (L IN+) input. To use the TPA0242 with a single-ended source, ac-ground the R IN+ and L IN+ inputs and apply the audio signal to the R LINE± and L LINE± inputs. Line and headphone inputs share common positive inputs. If using separate line and headphone inputs, R IN+ and L IN+ should be ac-grounded. If using differential inputs, line and headphone inputs must be the same. In a single-ended input application, the R IN+ and L IN+ inputs should be ac grounded at the audio source instead of at the device inputs for best noise performance.

3-6

Details

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Contents Users Guide Important Notice Preface Related Documentation From Texas InstrumentsPage Contents Figures TablesIntroduction Feature Highlights TPA0242 EVM Specifications DescriptionIntroduction ±2. Typical TPA0242 EVM Jumper Settings Quick StartPrecautions ±1. Quick Start Platform Map±3. Platform Jumper and Switch Settings for the TPA0242 Quick Start List for Platform±4. Typical TPA0242 EVM Jumper Settings ±2. Module PreparationQuick Start List for Stand-Alone ±3. Quick Start Module MapControl inputs Details ±1. The TI Plug-N-Play Audio Amplifier Evaluation Platform TPA0242 Audio Power Amplifier Evaluation Module ±2. TPA0242 EVM±3. TPA0242 EVM Schematic Diagram 1 TPA0242 Audio Amplifier IC±4. TPA0242 Amplifier IC Inputs and Gain±1. TPA0242 EVM BTL Volume Settings Differential InputBTL Operation Depop CircuitrySingle-Ended Operation EVM Insertion Installing and Removing EVM BoardsEVM Removal 2 TPA0242 Module Jumper Settings and Switches ±5. TPA0242 EVM Jumpers and Switches2.3 S3 Ð Input Mode Jumper 2.1 S1 Ð Shutdown Switch2.2 S3 Ð Output Mode Jumper 2.4 S4 Ð Input and Output Mode JumperSignal Conditioning Signal RoutingHeadphone Output Jack Headphone Jack Control Signals Mute Shutdown/ModeMute/Mode Select JP6 Mute/Mode Polarity Select JP8Power Requirements Inputs Inputs and OutputsOutputs ±2. Typical TPA0242 EVM Jumper Settings for BTL Stand-Alone Using The TPA0242 EVM Stand-Alone1 TPA0242 EVM Connected for BTL Output 2 TPA0242 EVM Connected for Single-Ended Output ±10. TPA0242 EVM Connected for Stereo Single-Ended OutputTPA0242 Audio Power Amplifier Evaluation Module Parts List ±4. TPA0242 EVM Parts List