The TAS2505-Q1 has a built-in LDO which can generate the analog supply (AVDD) also the digital supply (DVDD) from input voltage range of 2.7 V to 5.5 V with high PSRR. If combined power supply current is 50 mA or less, then this LDO can deliver power to both analog and digital power supplies. If the only speaker power supply is present and LDO Select pin is enabled, the LDO can power up without requiring other supplies. This LDO requires a minimum dropout voltage of 300 mV and can support load currents up to 50 mA. For stability reasons the LDO requires a minimum decoupling capacitor of 1 µF (±50%) on the analog supply (AVDD) pin and the digital supply (DVDD) pin. If use this LDO output voltage for the digital supply (DVDD) pin, the analog supply (AVDD) pin connected to the digital supply (DVDD) externally is required.

The LDO is by default powered down for low sleep mode currents and can be enabled driving the LDO_SELECT pin to SPKVDD (speaker power supply). When the LDO is disabled the AVDD pin is tri-stated and the device AVDD needs to be powered using external supply. In that case the DVDD pin is also tri-stated and the device DVDD needs to be powered using external supply. The output voltage of this LDO can be adjusted to a few different values as given in the Table 8-3.

For more detailed information see the TAS2505 Application Reference Guide (SLAU472).