SLASEM8A January 2019 – March 2019 TPA3255-Q1
PRODUCTION DATA.
The PVDD decoupling capacitors must be placed as close to the device pins a possible to insure short trace length and low a low inductance path. Likewise the ground path for these capacitors must provide a good reference and should be substantial. This will keep voltage ringing on PVDD to a minimum.
The voltage of the decoupling capacitors should be selected in accordance with good design practices. Temperature, ripple current, and voltage overshoot must be considered. This fact is particularly true in the selection of the 1μF that is placed on the power supply to each full-bridge. It must withstand the voltage overshoot of the PWM switching, the heat generated by the amplifier during high power output, and the ripple current created by high power output. A minimum voltage rating of 100 V is required for use with a 51-V power supply.
The large capacitors used in conjunction with each full-bridge, are referred to as the PVDD Capacitors. These capacitors should be selected for proper voltage margin and adequate capacitance to support the power requirements. In practice, with a well designed system power supply, 1000 μF, 80 V supports most applications. The PVDD capacitors should be low ESR type because they are used in a circuit associated with high-speed switching.