TDA2P-ACD: VSSA_OSCx connection to GND

Javier Julve

Prodigy 150 points

Part Number: TDA2P-ACD

Dear TI Team,

Source: SPRS996F –MARCH 2017–REVISED FEBRUARY 2019

Figure 5-12. Crystal Implementation. It is not clear enough either VSSA_OSCx must be connected to GND or not.

(Figure 5-14. 1.8-V LVCMOS-Compatible Clock Input. In this case it is quite clear connection to GND)

Therefore the following question arise at this point. Should be VSSA_OSCx (x=0, 1) connected to GND? If so, Analog GND or Digital GND? Is there please any requirement/specification/recommendation for a correct layout?

Thanks so much in advance. Best Regards,

Javi

over 6 years ago

0 Stanislav Stilyanov over 6 years ago

TI__Mastermind 25170 points

Javi,

Give me some mor etime to check internally.

0 Stanislav Stilyanov over 6 years ago

TI__Mastermind 25170 points

Javi,

I've also got confused at first look. However, Figure 5-12 seems to be correct - no connection to GND when crystal is used. See also TI EVM schematic.

Regards,

Stan

0 Javier Julve over 6 years ago in reply to Stanislav Stilyanov

Prodigy 150 points

Dear Stanislav,

Thanks so much for your reply.

I have checked EVM schematic (document named DRA76xP_DRA77xP_TDA2Px_ACD CPU Board Schematic Rev C available on TI web) and, forgive me if I am wrong, but oscillator is implemented instead of crystal. Therfore I can not use it as reference.

Anyway, I assume that "seems to be" is only a way to express yourself and thus you do not have any doubt about your answer: no connection to GND when crystal is used. Should I mark this thread as "resolved"?

Thanks so much. Best Regards,

Javi.

0 Stanislav Stilyanov over 6 years ago in reply to Javier Julve

TI__Mastermind 25170 points

Javi,

I contacted the datasheet team. They've been told (few years ago) to remove the GND symbol because this eliminates some issue with the oscillator timings.

Sorry I didn't check the actual J6Plus EVM board. I saw this on J6eco EVM, which is a sister SoC, thinking J6Plus also uses a crystal.

My intention was only to show that missing GND is not actually an error in the datasheet .

Thanks and regards,

Stan

0 Javier Julve over 6 years ago in reply to Stanislav Stilyanov

Prodigy 150 points

Hi Stanislav,

Thanks so much for your feedback. No more doubts from my side.

Best Regards,

Javi.

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TDA2P-ACD: VSSA_OSCx connection to GND