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OPA333-Q1: Quiescent current estimation

NOBUO FUJIHARA
Genius 9355 points
Part Number: OPA333-Q1

Hello Champs,

 

My customer asked how to estimate Iq_max at 85C and 60C.

 

From the datasheet (SBOS522-JUNE 2010), Iq_max(Ta 25C) = 25uA, Iq_max(overtemperature) = 30uA.

And from the graph of “QUIESCENT CURRENT vs TEMPERATURE”, Iq is reverse proportional to temperature.

 

Q.1) Iq_max(overtemperature) is quiescent current at -40C?

 

Q.2) According to “QUIESCENT CURRENT vs TEMPERATURE” graph, Iq at 25C and 60C, and 85C are almost identical value. So is it reasonable to say Iq_max at 60C and 85C is 25uA?

 

Thanks and best regards,

Nobuo Fujihara

  • 0
    TI__Guru* 93105 points

    Fujihara-san,

    Regarding your comments and questions:

    My customer asked how to estimate Iq_max at 85C and 60C. 

    From the datasheet (SBOS522-JUNE 2010), Iq_max(Ta 25C) = 25uA, Iq_max(overtemperature) = 30uA.

    And from the graph of “QUIESCENT CURRENT vs TEMPERATURE”, Iq is reverse proportional to temperature. - Note that the curve is "typical." That is usually an average of the devices that were characterized. Other devices from different production runs may have a somewhat different curvature. 

    Q.1) Iq_max(overtemperature) is quiescent current at -40C?  - The Electrical Characteristics table lists the maximum Iq over the -40 C to +125 C temperature range as 30 uA. Thus, the maximum Iq limit at -40 C is 30 uA. 

    Q.2) According to “QUIESCENT CURRENT vs TEMPERATURE” graph, Iq at 25C and 60C, and 85C are almost identical value. So is it reasonable to say Iq_max at 60C and 85C is 25uA? - The "typical" curves shows 25 C, 60 C and 85 C Iq levels to be very close and likely the Iq at 60 C and 85 C won't exceed 25 uA. But because there is an over-temperature Iq maximum of 30 uA it leaves the possibility open that some devices might have an Iq of 30 uA at those temperatures.

    Regards, Thomas

    Precision Amplifiers Applications Engineering

  • 0 in reply to Thomas Kuehl
    TI__Genius 9355 points
    Thomas-san,

    Thanks for your reply.
    I have further question and would like to ask off-line via e-mail.

    Thanks and best regards,
    Nobuo Fujihara