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Calculating Maximum Power Consumption or Current Consumption for TXS0108E and SN74LVC1T45

Atthen
Prodigy 60 points
Other Parts Discussed in Thread: TXS0108E, SN74LVC1T45, SN74AVC1T45

Hi,

I need to translate +5V I/O to +3.3V I/O with min datarate 60Mbps.

Can i know what is what is the max current consumption (Imax) for each voltage level translator below:

1. TXS0108E 

2. SN74LVC1T45

I'm connecting VccA : +3.3V, VccB : +5V. 

I couldn't find the info in the datasheet. I need to info for my power supply circuit design.

Thanks,

Regards,

Atthen

  • 0
    TI__Expert 4705 points

    Hi, Atthen,

    For the I max calculation, here is the formula to calculate it.

    I_total = I_dynamic + I_static

    For I_static, you can find the value in the datasheet. 

     I_dynamic = (Cpd+Cload) x Vcc x freq. For Cpd, please check with the Datasheet, and find the value for your power supply.Here I use the Cload is 0 for output port open. you can add your load and redo below calculation. anything, please let me know. 

    For TXS0108E:

    Based on the Dataheet, I_static for  IccA is 2uA, I_static for IccB is 6uA.

    IccA_dynamic calculation

    - For A-B direction worst case(8 Data lines are all switching, 60Mbps is 30MHz):

    ICCA_dynamic = Cpda_data_b x VccA x freq x8= 8pF x 3.3 x 8 data lines x 30M=6.336mA   

    - For B-A driection worst case(8 Data lines are all switching, 60Mbps is 30MHz):

    IccA_dynamic = Cpda_data_a x VccA x freqx8 = 9.8pF x 3.3 x 8 data lines x 30M=7.761mA  

    IccB_dynamic calculation

    - For A-B direction worst case(8 Data lines are all switching, 60Mbps is 30MHz):

    IccB_dynamic = Cpdb_data_b x VccBx freq x8= 23pF x 5 x 8 data lines x 30M=27.6mA   

    - For B-A driection worst case(8 Data lines are all switching, 60Mbps is 30MHz):

    IccB_dynamic = Cpdb_data_a x VccBx freqx8 = 20.9pF x 5 x 8 data lines x 30M=25.08mA

    IccA(max) =2uA+7.761mA =7.763mA  (I don't whether you direction is fixed, I chose the direction which has the maximum current)

    IccB(max)=6uA+27.6mA =27.606mA. (I don't whether you direction is fixed, I chose the direction which has the maximum current)

    For SN74AVC1T45, you can use the same method to calculate. anything, please let me know.

    BR
    junjie