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TXS0108E-Q1: How much quiescent current and operating supply current?

Yoshiki Ochi
Genius 9445 points
Part Number: TXS0108E-Q1
Other Parts Discussed in Thread: TXS0108E

Hi team, 

Could you tell me (1) how much quiescent current with VCCx input and no input/output logic change and (2) how much operating supply current with input/output logic change?

(1) quiescent current: "ICCA + ICCB Combined supply current" with "VI = VCCI or GND, IO = 0 " says 8uA, is it the current I would like to know?

(2) How could we calculate operating current? Is it related to data rate, input logic duty, output capacitance, how many CH it uses, quiescent current, and VCCx?

Regards,
Ochi

  • 0
    TI__Prodigy 460 points

    Hi Ochi,

    For (1) you are correct the 8uA value indicates the maximum quiescent current of the device when there is no output.

    For (2) there are a variety of factors that can impact the operating current of the device including load capacitance, frequency, and supply voltage. I recommend the application note CMOS Power Consumption and Cpd Calculation which goes into more detail on how to calculate these values for a specific situation. Note that for these calculations you will want to use the output supply (VCCO) in the equations. The FAQ How do I calculate power consumption or current consumption for my CMOS logic device may also be helpful.

    Thanks,

    Anthony

  • 0 in reply to Anthony Viviano
    TI__Genius 9445 points

    Hi Anthony, 

    Thank you for your supporting.

    I understood Ptotal = PS (quiescent current) + PT (internal CMOS capacitance current consumption for turning on and off) + PLC (external capacitive load current consumption for changing its logic) + PR (External load current consumption)

    Meaning that I consumption total = quiescent current (8uA) + internal CMOS charging current for these switching + capacitive and resistive load current, is it correct?

    Could you tell me Cpd value?

    By the way, I found that VOH minimum is 0.67*VCC. It means VOH minimum could be 3.35V if VCC=5.0V, is it correct?

    Regards,
    Ochi 

  • 0 in reply to Yoshiki Ochi
    TI__Prodigy 460 points

    Hi Ochi,

    Your I consumption equation above looks correct. For this device I recommend that you use the Cpd values given in the commercial version of the TXS0108E datasheet. For this device the Cpd values are expected to be the same between the commercial and automotive devices. See below for the Cpd values from the TXS0108E datasheet:

    You are also correct that when VCCB = 5V the VOH min = 3.35V. Please not that VCCB can range from 1.65V to 5.55V, but VCCA is limited to 1.4V to 3.6V per the recommended operating conditions.

    Thanks,

    Anthony