SLASEG8A March 2016 – July 2017 TAS5782M
The TAS5782M device requires two power supplies for proper operation. A high-voltage supply called PVDD is required to power the output stage of the speaker amplifier and its associated circuitry. Additionally, one low-voltage power supply which is called DVDD is required to power the various low-power portions of the device. The allowable voltage range for both the PVDD and the DVDD supply are listed in the Recommended Operating Conditions table. The two power supplies do not have a required powerup sequence. The power supplies can be powered on in any order. TI recommends waiting 100 ms to 240 ms for the DVDD power supplies to stabilize before starting I2C communication and providing stable I2S clock before enabling the device outputs.
The DVDD supply that is required from the system is used to power several portions of the device. As shown in Figure 83, it provides power to the DVDD pin, the CPVDD pin, and the AVDD pin. Proper connection, routing, and decoupling techniques are highlighted in the Application and Implementation section and the Layout Example section) and must be followed as closely as possible for proper operation and performance. Deviation from the guidance offered in the TAS5782M device Application and Implementation section can result in reduced performance, errant functionality, or even damage to the TAS5782M device.
Some portions of the device also require a separate power supply that is a lower voltage than the DVDD supply. To simplify the power supply requirements for the system, the TAS5782M device includes an integrated low-dropout (LDO) linear regulator to create this supply. This linear regulator is internally connected to the DVDD supply and its output is presented on the DVDD_REG pin, providing a connection point for an external bypass capacitor. It is important to note that the linear regulator integrated in the device has only been designed to support the current requirements of the internal circuitry, and should not be used to power any additional external circuitry. Additional loading on this pin could cause the voltage to sag, negatively affecting the performance and operation of the device.
The outputs of the high-performance DACs used in the TAS5782M device are ground centered, requiring both a positive low-voltage supply and a negative low-voltage supply. The positive power supply for the DAC output stage is taken from the AVDD pin, which is connected to the DVDD supply provided by the system. A charge pump is integrated in the TAS5782M device to generate the negative low-voltage supply. The power supply input for the charge pump is the CPVDD pin. The CPVSS pin is provided to allow the connection of a filter capacitor on the negative low-voltage supply. As is the case with the other supplies, the component selection, placement, and routing of the external components for these low voltage supplies are shown in the TAS5782M and should be followed as closely as possible to ensure proper operation of the device.
The output stage of the speaker amplifier drives the load using the PVDD supply. This is the power supply which provides the drive current to the load during playback. Proper connection, routing, and decoupling techniques are highlighted in the TAS5782MEVM and must be followed as closely as possible for proper operation and performance. Due to the high-voltage switching of the output stage, it is particularly important to properly decouple the output power stages in the manner described in the TAS5782M deviceApplication and Implementation . Lack of proper decoupling, like that shown in the Application and Implementation , results in voltage spikes which can damage the device.
A separate power supply is required to drive the gates of the MOSFETs used in the output stage of the speaker amplifier. This power supply is derived from the PVDD supply via an integrated linear regulator. A GVDD_REG pin is provided for the attachment of decoupling capacitor for the gate drive voltage regulator. It is important to note that the linear regulator integrated in the device has only been designed to support the current requirements of the internal circuitry, and should not be used to power any additional external circuitry. Additional loading on this pin could cause the voltage to sag, negatively affecting the performance and operation of the device.