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ADS7841-Q1: supply current

na na78
Guru 16770 points
Part Number: ADS7841-Q1

Hi

1.

We want a graph that shows Supply Current vs Temperature at VCC=5V. We can see the one of VCC=2.7V, but VCC=5V is not on the datasheet.

Do you have it?

2.

According to the datasheet, Iq(max) is 650uA at VCC=2.7V as the electrical characteristics.

while, the graph of Supply current vs Temperature seems ~320uA as the maximum supply current in all temperature range.

What is the cause of increasing current to the maximum?

Could you show us a graph offering a characteristics showing maximum supply current at VCC=2.V and VCC=5V each.

BestRegard

  • 0
    TI__Mastermind 21685 points
    Hi,

    1. Sorry, we don't have a supply current vs temperature graph at VCC=5V.

    2. Supply current versus temperature graph is typical chararacteristics (not maximum). Whereas table shows the maximum limit (650uA). Also, you can see table shows the typical value at 25C is 280uA (at 2.7V) which corresponds to the value shown in typical characteristics graph.

    Thanks,
    Vishy
  • 0 in reply to Vishy Viswanathan
    TI__Mastermind 21685 points

    Hi,

    In the electrical characteristics table, note there is Iq specification both at 5V and 2.7V. The maximum limit at 5V for Iq is 900uA and as we discussed above the maximum limit for 2.7V is 650uA. Please see below

    At 5V

    AT 2.7/V

  • 0 in reply to Vishy Viswanathan
    Guru 16770 points
    Hi Vishy

    Thank you for your reply.

    I understood the graph shows typical characteristics.

    In fact, we want to suppose the characteristics between maximum supply current vs temperature.

    The typical supply current vs temperature graph at VCC=2.7V looks linear.

    What characteristics can we assume for maximum supply current in recommended operational temperature?

    Is linearity of characteristics same for maximum supply current?

    BestRegards
  • 0 in reply to na na78
    TI__Mastermind 21685 points
    Hi,

    I would suppose so but for any design calculation it's better and safe to use the worst case number (650uA at 2.7V and 900uA at 5V).

    Thanks,
    Vishy
  • 0 in reply to Vishy Viswanathan
    Guru 16770 points
    Hi Vishy

    Thank you for your reply.

    >I would suppose so but for any design calculation it's better and safe to use the worst case number (650uA at 2.7V and 900uA at 5V).
    Yes. I also suggested that the use of worst case number should be used for a design.

    However, we want to understand if there is the tendency of characteristics of ADS7841Q1 for max supply current vs temperature.
    (EX. The lower temperature, the more supply current would consume according to the supply current vs temperature figure, etc..)

    Can you have answer?

    BestRegards
  • 0 in reply to na na78
    TI__Mastermind 21685 points
    Hi,

    One way to think about this: the graph shows what's the typical variation of Iq over temperature whereas the table limits worst variation at any given temp (max 650uA at 2.7V).

    I am checking if we have any additional data on this. In the absence, it is best to assume Iq(max) over temp at 5V is 900uA (and 650uA at 2.7V).

    Thanks,
    Vishy
  • 0 in reply to Vishy Viswanathan
    Guru 16770 points
    Hi Vishy

    Thank you for your support.

    >I am checking if we have any additional data on this. In the absence, it is best to assume Iq(max) over temp at 5V is 900uA (and 650uA at 2.7V).
    The previous one is final answer, OK?

    BestRegards
  • 0 in reply to na na78
    TI__Mastermind 21685 points
    Hi,
    I checked about this: Except for the max Iq current limit as provided in the data sheet, sorry we don't have any additional data of max current variation with temperature.
    Thanks,
    Vishy