ADS52J90EVM: ADS52J90 EVM external reference voltage

Rizwan Tariq Syed

Part Number: ADS52J90EVM
Other Parts Discussed in Thread: ADS52J90, PGA5807A

Hey Guys

I am using TI's High speed ADC board ADS52J90EVM.

Voltage levels of my input signal are very low. i.e. 1 mv to 2 mv. in default configuration reference voltage of ADC is a big number. therefore i cant really utilized the full range of ADC.

is it possible to apply the external reference voltage ?

on this user guide, page number 20, it is written 'TP20 FORCE_VREF Analog inputs Can provide external VREF to ADS52J90 by installing R109' . Does this mean that we have to solder a resister at R109 at its place and apply the external voltage .

Do we need to take care of anything else while applying external reference voltage ?

Looking forward for your reply.

Best Regards

Rizwan

over 7 years ago

0 Rizwan Tariq Syed over 7 years ago

Prodigy 250 points

user guide link : www.ti.com/.../slau632b.pdf

0 Praveen Aroul over 7 years ago in reply to Rizwan Tariq Syed

TI__Mastermind 49956 points

Hi Rizwan,

External voltage reference is not supported in ADS52J90.
This was included in the EVM as an internal test mode and has not been characterized.

Can you provide more details about your application?
What is the signal source? You may want to amplify the input signal before going to the ADC.
Have a look at our Analog Front End solution specifically AFE58xx family of devices that includes the VCA and ADC cores in a single chip.

0 Rizwan Tariq Syed over 7 years ago in reply to Praveen Aroul

Prodigy 250 points

Hi Parveen

Thanks for your quick reply.
It is clear to me, we cannot change the reference voltage.

We are using TI's ADC with our FMCW Radar sensor. we are using this sensor for object detection. The voltage levels are 1 to 2 mv.

In ADS52J90 EVM, there are two differential channels as well. i.e. SMA_CH7, SMA_CH7a , SMA_CH8, SMA_CH8a
On SMA_CH8 differential channel there is an amplifier as well.

What is your opinion, can we make use of either of these two differential channel in this case ?

Best Regards
Rizwan

0 Praveen Aroul over 7 years ago in reply to Rizwan Tariq Syed

TI__Mastermind 49956 points

Hi Rizwan,

Yes you should be able to use either of the differential channels for your evaluation with the ADS52J90 EVM.
For your product, if you are looking for multichannel PGAs, then you may want to look at the PGA5807A.

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ADS52J90EVM: ADS52J90 EVM external reference voltage