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ads1282 modulator check up

ralph reiter
Prodigy 95 points
Other Parts Discussed in Thread: ADS1256, ADS1282, OPA1632

Hi i am using the ads1282 evm with an arm microcontroller which i had used with an ads1256 evm previously.

i have now modified the program code quickly and all i get out of the ads1282 is FFFFFFFF as ADC Code.

i had also the problem that a cable on my power supply  the 5 Volt positiv supply got off so i measured -1.6V on the analog input pin ,

now i think that maybe the ads1282 modulator is destroyed, thats why i ask you if this could be the case, also i measured 50 mA on the postiv supply as current draw and

the ads1282 gets slightly warm (about 35°C)

Can the ADS1282 be broken ? What can i check? I think i will now put a scope on the direct modulator output to see whats happening?

 

Thank you in advance for your answer.

Ralph Reiter

E-Mail: ralph.reiter@uni.lu

  • 0
    Prodigy 95 points

    It is still sometimes very useful to use an oscilloscope, because i checked now the direct modulator output and it let me believe that the converter works correct.

    I checked then the data output pin with the modulator direct output then disabled and it looked like there was the problem.

    i had a bad contact on the data outpin of the evm board.

    I must say that it was not a fault of the evm board, but i had broken the connection by desoldering the pcb connector on the evm board.

    Now everything seems to work.

    Thank you bye bye.

  • 0 in reply to ralph reiter
    TI__Guru* 97465 points

    While 50mA does seem like quite a bit of current, I would note that there are two OPA1632 buffers and an oscillator that probably use the bulk of that current.

    The ADS1282 runs with about 5mA - even in high resolution mode.

    Joseph Wu

  • 0 in reply to Joseph Wu
    Prodigy 95 points

    yes but i think that it is normal as i use already one LM7809 + one LM7805 + one LM7909 + L1086-3.3

    on the positiv supply the board draws ca 50 mA

    on the negativ side ca 30mA

    as on the negativ side there are only the OPA1632 buffers that are supplied + the regulator current draw  we see that the input buffers seem to draw most of thecurrent.

    thanks for your answer my converter seems now to work i must only verify that my output code is correct.