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TLV2402-Q1: TLV2402 higher supply current

Intellectual 980 points

Replies: 4

Views: 146

Part Number: TLV2402-Q1

Dear forum Members,

I experienced the supply current is too high if device output saturated (however, not loaded!). One of the channels used as comparator and the other one in linear mode.

If comparator output settleted to VSS then supply current is ca 5,5uA, at VDD the current ca 13uA ("+" input is tied to 1,2V, "-" is to VSS)

If both channels are operated in linear mode the current drawn is onyl 1,7uA as specified (for this condition "comparator" channel formed to an unity gain buffer with "+" =1,2V).

Supply voltage is 7V (single supply application).

Is this property normal for this device? If so,  can you please expalin why the current draw varies despite the output is left unconnected?

Can you please suggest a solution becasue the need for low current is critical my design.

Thanks in advance!

Regards,

Joseph

  • Joseph,

    Everything is normal except for IDD not being equal to ISS. The input current should be effectively be zero. That coupled with an open output means the positive and negative supply current must be equal. 

    I tested the supply current with supply voltage at 2.5V (similar result for 7V or 16V).

    Input voltage is the X axis. The comparator mode difference voltage is swept from -2.5V to +2.5V.  The linear mode unity gain input voltage is swept from -0.1V to 2.6V

    Supply current increases when output is fully VOH or as output approaches VOL.

    I checked for other Q1 rated dual op amps at 7V and nothing was lower power. Perhap the comparator could be configured in such a way to limit output voltage to less than VSS to VDD.  I haven't done this before, but will try implement this idea.

    Regards,
    Ronald Michallick
    Linear Applications

    TI assumes no liability for applications assistance or customer product design. Customer is fully responsible for all design decisions and engineering with regard to its products, including decisions relating to application of TI products. By providing technical information, TI does not intend to offer or provide engineering services or advice concerning Customer's design. If Customer desires engineering services, the Customer should rely on its retained employees and consultants and/or procure engineering services from a licensed professional engineer (LPE).

     

  • In reply to Ron Michallick:

    Hi Ron,

    thanks for the investigation. Interesting to note, simulating the '2402 using TINA the supply current was still 1,78uA in comparator mode (when output was at L) and 4,15mA (!) in H level.

    Maybe the large differential signal changes the internal biasing of the 2402. 

    Regards,

    Joseph

  • In reply to Joseph82:

    Joseph,

    Yes, the biasing is sensitive to non-linear operation. I wasn't able to make a circuit to keep the device linear and perform a comparator function. 

    Regards,
    Ronald Michallick
    Linear Applications

    TI assumes no liability for applications assistance or customer product design. Customer is fully responsible for all design decisions and engineering with regard to its products, including decisions relating to application of TI products. By providing technical information, TI does not intend to offer or provide engineering services or advice concerning Customer's design. If Customer desires engineering services, the Customer should rely on its retained employees and consultants and/or procure engineering services from a licensed professional engineer (LPE).

     

  • In reply to Ron Michallick:

    Hi Ron,

    no problem, thank you vm for the effort!

    Regads,

    Joseph

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