ADC12DJ3200: grounding for three ADC12DJ3200 on single board

LALIT VERMA

Part Number: ADC12DJ3200
Other Parts Discussed in Thread: LMK04828, LMX2582, TIDA-01028

Hi TI,

We are using three ADC12DJ3200 in our design.

In eval board for ADC12DJ3200, single ground is used for all components viz. ADC12DJ3200, LMK04828,LMX2582 and all regulators.

But in TI TIDA-01028 design, in which two ADC12DJ3200 are used, separate grounds are used ,for example one ground for analog front end ,other for regulators and another one for components like ADC,LMK,LMX etc.

All ground are connected using zero ohm resistors.

I have heard sometimes separate grounds could create more problems than using single uniform ground plane.

What are the thoughts of TI for grounding scheme for our application?

Thanks,

Lalit

over 4 years ago

0 jim s over 4 years ago

TI__Guru* 91947 points

Lalit,

We are looking into this.

Regards,

Jim

0 Jim Brinkhurst1 over 4 years ago in reply to jim s

TI__Mastermind 43820 points

Hi Lalit
My recommendation is to use a single unified ground plane system (multiple ground layers) with no splits for all ADCs and clock devices in your design.
Component placement and signal routing should be done to keep noisy circuitry and signals away from more noise sensitive devices and signals.
In particular the analog input signals and input clock should be routed so they are isolated from other clocks, data outputs and logic control signals that may be switching while the system is in operation.
Best regards,
Jim B

0 LALIT VERMA over 4 years ago in reply to Jim Brinkhurst1

Expert 1635 points

Hi Jim,
Can we also use that same ground for switching regulators and LDOs in our design.?
That is can we use one single uniform ground (without separating ground plane into AGND,DGND or PGND) for all the components(ADCs,PLLs,Regulators) ?

Thanks,
Lalit

0 Jim Brinkhurst1 over 4 years ago in reply to LALIT VERMA

TI__Mastermind 43820 points

Hi Lalit
Yes, a single ground for all devices.
Please follow the layout guidelines listed in the datasheets for all devices to give best performance and minimize noise transmission/coupling to other components.
Best regards,
Jim B

0 LALIT VERMA over 4 years ago in reply to Jim Brinkhurst1

Expert 1635 points

Hi Jim,
Thanks for your suggestions.

Lalit

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ADC12DJ3200: grounding for three ADC12DJ3200 on single board