• State TI Thinks Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 1 answer
  • Subscribers 46 subscribers
  • Views 179 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Original question:

ads1282-ht: bit toggling in output data

ADS1282-HT: ADS1282

Knute Ray
Prodigy 230 points
Part Number: ADS1282-HT

Using a single supply of 5V, the reference should also be 5.0V with the Vref+ at 5.0 and the Vref- to gnd? Is this correct? With a differential amplifier driving Vin+ and Vin -, If this voltage went to 0 or 5V can the part tolerate this? Thanks.

  • 0
    TI__Mastermind 23050 points

    Hi Knute,

    It does depend a bit on which voltage you are talking about. A 5V reference is fine with a 5V AVDD. If you use the PGA with a gain of one, then per the input range equation your full scale input range would be +/-2.5V differentially. You must also adhere to the absolute input range though, which is the maximum voltage you can put on a single pin. In this case it would be 3.75V (AVDD-1.25). You can think of this as effectively placing a limit on where you should set your common-mode. A +2.5V differential signal means one input will move +1.25V and one will move down -1.25V. Since the largest voltage you can have on the input is 3.75V, your common-mode should not be greater than 2.5V. Similar logic applies to the low end, but the input range is a little more forgiving allowing you to swing to AVSS + 0.7V. Hope that helps!

    Best,

    Zak  

  • 0 in reply to Zak Kaye
    Prodigy 230 points

    Thanks.  If the input voltage goes overrange to 0V or 5V, the conversion will not be good but will the part be damaged?  The absolute maximum spec for the analog input voltage is VSS-0.3 to VDD+0.3, which in this case is -0.3V to 5.3V.

  • 0 in reply to Knute Ray
    TI__Mastermind 23050 points

    Hi Knute,

    The part should not be damaged, but as you mention the conversion will be invalid as the PGA goes into saturation. There would be some overload recovery time associated with this as well.

    Best,

    Zak