ADS54J40: Is ADC32RF45/ADS54J40 ENOB frequency dependent

Aravind Venkitasubramony

Part Number: ADS54J40
Other Parts Discussed in Thread: ADC32RF45,

I see that the ENOB for the ADS54J40 is 11.2 whereas for the ADC32RF45 is 9.7. I wanted to check if the low ENOB for the ADC32RF45 is only this low at the max rate of 3GSPS i.e. if I operate the chip at a lower clock speed at 1GSPS, would i get comparable ENOB as ADS54J40?

over 7 years ago

0 jim s over 7 years ago

TI__Guru* 91947 points

Aravind,

We are looking into this and will get back to you shortly.

Regards,

Jim

0 jim s over 7 years ago in reply to jim s

TI__Guru* 91947 points

Aravind,

Due to the fact that the ADC thermal noise of ADC32rf4x is ~ 63dBFS, the ENOB will not get better at slower clock rate.

Regards,

Jim

0 Aravind Venkitasubramony over 7 years ago in reply to jim s

Intellectual 835 points

Thank you very much! That is a very useful information to have.

Also could you confirm what do you actually mean by the parameter Analog input bandwidth 1200MHz that is mentioned in the spec sheet. At 1GSPS one cannot cover 1200MHz right. Is the 1200MHz just the bandwidth over which one gets a good s11? Is this parameter explained in detail in the spec sheet anywhere?

0 jim s over 7 years ago in reply to Aravind Venkitasubramony

TI__Guru* 91947 points

Aravind,

This bandwidth can be captured by the ADC, but when the input is above Fs/2, this is called aliasing or under sampling. More info regarding this can be found in section 3 of the attached document.

Regards,

Jim

0550.ADC Basics.pdf

Data converters

Data converters forum

ADS54J40: Is ADC32RF45/ADS54J40 ENOB frequency dependent