TAS5548: peripheral components for PIN VR_ANA

JIM WANG

Part Number: TAS5548

Hi Officer,

I am just writing to ask what kind of peripheral components shall be put for pin VR_ANA.

The pin description on she datasheet shows that 'A 0.1-µF low-ESR capacitor should be connected between this terminal and AVSS_PLL. This terminal must not be used to power external devices.'

while the layout guideline on the datasheet provides such a schematic. I do not understand the components used between VR_ANA and PLL_FLTP, and those ones between PLL_FLTM and AVSS,

CAN you please help on this?

thanks,

Jim.

over 6 years ago

0 Andy Liu (BMS) over 6 years ago

TI__Guru 52115 points

I will have my colleague take a look.

0 Robert Clifton56 over 6 years ago in reply to Andy Liu (BMS)

TI__Mastermind 27320 points

Hi Jim,

Can you please tell me what about these components you're not understanding so that I can better explain it?

Thanks,
Robert Clifton

0 JIM WANG over 6 years ago in reply to Robert Clifton56

Prodigy 200 points

Hi Robert,

Thanks for your reply.

On TAS5548 datasheet, in the pin descriptions, for pin VR_ANA it says 'A 0.1-µF low-ESR capacitor should be connected between this terminal and AVSS'.

While according to the layout example from the same datasheet (attached above), there is no such 0.1 UF cap between VR_ANA and AVSS.

Instead, they put filters in between VR_ANA and PLL_FLTP, and PLL_FLTM and AVSS.

I am just confused by why this layout example shows different way of layout from the pin description.

thanks,

Jim.

0 Robert Clifton56 over 6 years ago in reply to JIM WANG

TI__Mastermind 27320 points

Hi Jim,

Actually they are still connected but through the filter on the PLL pins. You can still have a capacitor directly connecting VR_ANA to AVSS while retaining the filter for PLL_FLTP and PLL_FLTM but the configuration we in the datasheet provides the lowest noise in the system.

Best Regards,
Robert Clifton

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TAS5548: peripheral components for PIN VR_ANA