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TPA3251: TPA3251/3255 GVDD/VDD Decoupling

Part Number: TPA3251
Other Parts Discussed in Thread: PMP11769

Hello everyone,

quick question about the VDD/GVDD Supply of the Akima-ICs:

Following the reference designs, the +12V is provided by a DCDC + Post-Linear Regulator.

--> Since the Supply is unipolar and the Input-Opamps are directly feed by +12V, it might make sense to either use a Post-Reg or a capacitance multiplier.

In the PMP11769, no post-reg is used, but another LC-Filter at the DCDC output. As from my knowledge, no post-reg is needed here since the supply is a bipolar one and the PSRR of the Opamps is way enough in fs-regions.

The question which arises here, supplying ONLY the TPA's VDD & GVDD, no further post-reg or buffer should be needed on the +12V without harming performance i think?

GVDD should not care about some mV Ripple anyway, and the DVDD/AVDD which are derived from the VDD input are each generating with seperate LDO, therefore a post-reg is already "in place" here.

--> if only the TPA is supplied with +12V, and no other OPAMPS or analog circuits, using a simple 12V-buck without additional filtering is sufficient to reach EVM-Performance value. Am i right here?

Thanks already, 

best regards,