ADC12DJ3200EVM: PCB

new2day

Expert 1970 points

Part Number: ADC12DJ3200EVM
Other Parts Discussed in Thread: ADC12DJ3200

I like ot know the PCB material and layer stack-up of ADC12DJ3200EVM. Thank you.

over 8 years ago

0 Jim Brinkhurst1 over 8 years ago

TI__Mastermind 44680 points

Hi new2day

Data for the board design, including stackup, layer plots, etc. is available here:

/cfs-file/__key/communityserver-discussions-components-files/73/8203.HSP001_2D00_ADC12DJ3200EVM_2D00_Rev_2D00_A.zip

Best regards,

Jim B

0 new2day over 8 years ago in reply to Jim Brinkhurst1

Expert 1970 points

It's Megtron 6 from Panasonic.

I like to check

1. Was there any reason not use Rogers 4350B on top layer, for example?

2. Megtron 7, the next Gen material would be better, right?

Thank you.

0 Jim Brinkhurst1 over 8 years ago in reply to new2day

TI__Mastermind 44680 points

Hi new2day

We generally will use Rogers 4350B or Megtron 6 materials on our high speed board designs, but we don't mix the materials in the same board.

The choice of which is uses can sometimes depend on material availability at the board vendors we work with.

I have not investigated Megtron 7 yet.

Best regards,

Jim B

0 new2day over 8 years ago in reply to Jim Brinkhurst1

Expert 1970 points

Hi,

Have take a look the EVM schematics and noticed that the input circuit are now simplified compare to E3 version. There are only a Balun and a 0 ohm resistor on each leg.

1. May I ask the reason of removing those resistor network on the E3 version?

2. This ADC support both AC and DC coupling on the INA+/- and INB+/-. May I ask the reason of using DC coupling on EVM not AC?

Thank you.

Regards,

Ying

0 Jim Brinkhurst1 over 8 years ago in reply to new2day

TI__Mastermind 44680 points

Regarding the latest questions.

The extra resistors were removed to remove parasitic elements in the signal path from balun outputs to ADC inputs.
The ADC12DJ3200 differential analog inputs have a 0V common mode. Because of this it isn't necessary to AC-coupled the ground referenced balun outputs to the analog inputs. On ADCs with a non-0V common mode, the capacitors are used to allow the analog inputs to self bias at the proper voltage, while the balun outputs remain at their proper common mode.

Best regards,

Jim B

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ADC12DJ3200EVM: PCB