ADS54J42: ADS54J42 Schematic Review?

HENRY JUNG

Expert 2030 points

Part Number: ADS54J42
Other Parts Discussed in Thread: ADC32J45,

DEARS.

The customer designs the ADC32J45 and ADS54J42.

The ADC32J45 has design experience.

But the ADS54J42 is first designed.

Please review the ADS54J42 related circuit.

There was a SNR related issue when using ADC32J45.

Please review the ADS54J42 for possible SNR issues.

Thank you

over 5 years ago

0 HENRY JUNG over 5 years ago

Expert 2030 points

DEARS.

The level input to the ADC is fixed at -10dBm.
In the case of ADC32J45, the Vpp reference can be controlled.(Datasheet 53page)
We know that the higher the input level, the better the SNR.
However, our input level is fixed.
How can I improve the SNR at fixed input levels?
Does the ADS54J42 have a register value that can change the Vpp like ADC32J45?

Thank you.

0 Brian2001 over 5 years ago in reply to HENRY JUNG

TI__Intellectual 2750 points

Hello Henry,
I have sent this question to an engineer that works with the ADS54J42
Regards,
Brian

0 jim s over 5 years ago

TI__Guru* 91947 points

Henry,

The schematic appears to be fine. What is sourcing the clock? SNR is directly related to the phase noise of the clock. If you want better SNR, provide a cleaner clock.

Regards,

Jim

7737.Clocking High Speed Data Converters - 3_17_2013.pptx

0 jim s over 5 years ago in reply to HENRY JUNG

TI__Guru* 91947 points

Henry,
There is no register to change the Vpp.
Regards,
Jim

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ADS54J42: ADS54J42 Schematic Review?