ZHCSMX0B September 2019 – December 2020 TPA6304-Q1
PRODUCTION DATA
The gain of the TPA6304-Q1 is configurable in the Miscellaneous Control Register 2 through I2C. There are four gain settings of 10 dB, 16 dB, 22 dB, and 28 dB. 28 dB is the default setting. It is recommended to select the lowest possible gain for the expected PVDD operation and input voltage range to optimize dynamic range performance.
The combination of input voltage range and supply voltage sets the requirement for the chosen gain setting. In a typical application with maximum input signal amplitude of 0.5 Vrms and 14.4 V supply voltage the default gain of 28 dB allows for full output power of the device.
The input impedance for the IN_1, IN_2, IN_3 and IN_4 pins is typically 80 kΩ and independent of the gain setting. The input impedance for the IN_REF input is typically 20 kΩ.
The inputs need to be AC-coupled to minimize the output DC-offset and ensure correct ramping of the output voltages during power-ON and power-OFF. Time constants for all inputs, IN_1, IN_2, IN_3, IN_4 and IN_REF need to match. The input AC-coupling capacitor together with the input impedance forms a high-pass filter.
If a flat frequency response is required down to 20 Hz the recommended cut-off frequency is a fifth of that, 4 Hz. This can be achieved with a 0.47 μF ac-coupling capacitor.
It is recommenced to use AC-coupling capacitors with low leakage current, like ceramic-, film- or quality electrolytic-capacitors.
The TPA6304-Q1 has an output DC detection built in to protect the attached speaker in case an input AC-coupling capacitor fails or has too high leakage current.