AFE4300 VLDO voltage

Kent Wang

Other Parts Discussed in Thread: AFE4300

Hi TI friends,

I am designing a BCM with TI AFE4300. I have a question about VLDO:

The VLDO on AFE4300 is used to supply load cell bridge and it is spec-ed as ~1.7V. However, the load cell bridges I found so far are usually supplied with 5V voltage. A given weight will generate smaller voltage variation with 1.7V supply on a specific bridge than 5V supply. Can AFE4300 handle the bridge which usually supplied by 5V? Does AFE4300 have any requirement on load cell bridge?

Thanks & BR

Kent Wang

over 9 years ago

0 Praveen Aroul over 9 years ago

TI__Mastermind 49176 points

Hello Kent,

We have received your inquiry regarding the AFE4300 and hope to have some answers back to you shortly.

0 Kent Wang over 9 years ago in reply to Praveen Aroul

Prodigy 30 points

Thanks, Praveen. Waiting for your answers.

Best Regards,

Kent Wang

0 Praveen Aroul over 9 years ago

TI__Mastermind 49176 points

Kent,

So long as the input common mode is within the rails of the AFE4300, then it should be fine to provide an external supply to the load cell bridge. But the advantage of the ratiometric measurements is lost.

In order to get better performance, ratiometric measurements (same source for bridge excitation voltage and ADC reference voltage) has been used in AFE4300. This eliminates the effect of drifts and low frequency noise in the voltage source. AFE4300 integrates a ref and LDO that generates a 1.7V supply that can used as the excitation source for the load cells, thus simplifying ratiometric measurements.

Regards

Praveen.

0 Kent Wang over 9 years ago in reply to Praveen Aroul

Prodigy 30 points

Praveen,

Thanks for the tech info.

Regards,

Kent

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AFE4300 VLDO voltage