how to connect power ground and analog ground to a single ground?

vijay kumar24

Other Parts Discussed in Thread: LMZ31530, LMZ31710, LMZ31707

In our design only +12V and a single common ground is available from back
plane. But the TI Power supply module (LMZ31707) requires two separate
grounds. So, how this can be accomplished?

over 10 years ago

0 J Arrigo over 10 years ago

TI__Mastermind 28020 points

The AGND is already connected to PGND internal to the device. Your single ground should be connected to PGND. The AGND pins should be connected together on the PCB, and the connection internal to the device makes the connection to PGND.

0 vijay kumar24 over 9 years ago in reply to J Arrigo

Intellectual 305 points

Hi Arrigo,

What does "AGND pins should be connected together on the PCB" mean, does it mean AGND pins must be just connected to Pads of the PCB, where those Pads wont be having any connection to the ground on the PCB?

0 J Arrigo over 9 years ago in reply to vijay kumar24

TI__Mastermind 28020 points

All AGND pins of the device must be connected to one another. The routing of your PCB must make sure that all AGND pins are connected to one another.

0 vijay kumar24 over 9 years ago in reply to J Arrigo

Intellectual 305 points

Hello Arrigo,

In the Datasheet of LMZ31530, it is clearly mentioned that AGND is connected to PGND internally. But in the Datasheet of LMZ31707 or LMZ31710, it is no where mentioned that AGND is connected to PGND internally.

So, can you just check the datasheet of LMZ31710 & LMZ31707 and reconfirm me exactly whether AGND & PGND are connected internally or not?

0 Tom Guerin over 9 years ago in reply to vijay kumar24

TI__Mastermind 38230 points

Vijay:

LMZ31710 & LMZ31707 AGND & PGND are connected internally We do not recommend an external connection between AGND and PGND:

Note Insure analog ground pins 2,23 are connected externally only to each other.

tom

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how to connect power ground and analog ground to a single ground?