ADS1292: Reference voltage problem

Annie Liu

Part Number: ADS1292
Other Parts Discussed in Thread: ADS1298

Hi Team,

Customer is using ADS1292 / QFN32 chip. AVDD-AVSS | DVDD-DVSS are powered by + 3.3V, internal clock is selected. CONFIG2. The PDB_REFBUF bit has been set to 1, and the reference voltage is selected to be 2.42V. Digital SPI communication sequence is normal, ADS1292 can normally generate data ready interrupt. The channel data read are: Channel 1: 0X7FFFFF Channel 2: 0X800000 (channels 1-2 are all floating).

Question: Use a multimeter to measure the voltage between VREFP and VREFN (GND) to -0.075V.

Thanks,

Annie

over 3 years ago

0 Alexander Smith over 3 years ago

TI__Mastermind 47625 points

Hi Annie,

A negative reference voltage is incorrect, and will return FS+/- values as the customer has seen.

This could be due to a hardware issue (lines crossed, improper capacitors on VREF or VCAP circuits). This could also be an issue with the power-up routine. The power-up routine can be verified using the BIOFAQ:https://e2e.ti.com/support/data-converters/f/73/p/772058/2855202

https://e2e.ti.com/support/data-converters/f/73/p/775262/2868427#2868427

Does the ID register return correctly?

0 Annie Liu over 3 years ago in reply to Alexander Smith

TI__Genius 10295 points

Hi Alex,

Sorry, I just got feedback from customer.

He hasn't read the ID register. The PCB he made is based on the official schematic. The two capacitors connected in parallel between VREFP and VREFN are 10UF/10V 100NF/25V.

The program to debug ADS1292 is the one used on ADS1298. At that time, a normal reference voltage can be generated, and the channel data reading is also normal.

Thanks,

Annie

0 Alexander Smith over 3 years ago in reply to Annie Liu

TI__Mastermind 47625 points

Hi Annie,

Great, glad to hear that the customer was able to resolve their issue. Please let me know if there are additional questions.

Data converters

Data converters forum

ADS1292: Reference voltage problem