Texas Instruments SLOU023A manual 3.2.2Module Gain, Details

The TPA112 MSOP Audio Power Amplifier Evaluation Module

3.2.2Module Gain

The TPA112 MSOP evaluation module has a set gain of 4 (inverting) for each channel. However, the gain can be adjusted to a maximum of approximately 10 (inverting) by changing the value of feedback resistors (R8 and R10, Figure 3–3). Use the following equation to determine the value of RF:

Gain +– RF

RI

The TPA112 amplifier IC, like most other amplifiers, exhibits its best distortion and noise performance at lower gain levels. In addition, higher gain levels require a small compensation capacitor to ensure stability (see the TPA112 data sheet).

Gain versus total harmonic distortion (THD) and gain versus signal-to-noise ratio (SNR) should be considered in each application. Both the module input signal level and the TPA112 MSOP module gain should be adjusted to obtain the lowest overall distortion level for a particular overall gain. A quick rule of thumb (everything else being equal): the module input signal level should be as high as possible without clipping or overloading the TPA112 input, and the TPA112 gain should be kept as low as possible.

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