• State Resolved
  • Locked Locked
  • Replies 3 replies
  • Subscribers 20 subscribers
  • Views 335 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

SN74LVC8T245: How to calculate ICC

Yuta Nishie
Genius 4975 points
Part Number: SN74LVC8T245

Hi,

I have a question about Icc. I would appreciate it if you could answer.

1. Why is the maximum value of ICCA + ICCB 25uA instead of 30uA(=15uA+15uA)? Could you tell me why?

2. Is it correct to understand that ΔICCA is the value for 1 port and that the ΔICCA(max) when using 8 ports is 450uA?

Or do you want to add ICCA(max) as well? ΔICCA(max)=450uA+15uA=465uA?

3. Is it correct to understand that ΔICCB(max_8 port)=400uA? Or ΔICCB(max_8 port)=415uA?

4. Is the total current consumption ΔICCA(A port+DIR)+ΔICCB＋ICCA＋ICCB = 8x50uA + 50uA + 8x50uA + 25uA=875uA?

Best Regards,

Nishie

  • +1
    Guru 316760 points

    1. The worst case on the A side and the worst case on the B side cannot happen at the same time.

    2. ΔICC is measured per pin. It describes what happens when you apply an invalid voltage (0.6 V below the supply) to an input. If the input voltage goes even further away from the supply, near VCC/2, ΔICC becomes larger than the specified value. Anyway, during normal operation, this should not happen.

  • 0 in reply to Clemens Ladisch
    Genius 4975 points

    Hi Clemens-san,

    Clemens Ladisch said:
    1. The worst case on the A side and the worst case on the B side cannot happen at the same time.

    ->When "ICCA + ICCB" was measured, what were the conditions for A Port and B Port?

    2. Is it correct to understand that under normal operation, it would be below?

    B data to A bus(8 port): ICC(Total)<<8x50uA

    A data to B bus(8 port): ICC(Total)<<8x50uA+50uA

    Best Regards,

    Nishie

  • +1 in reply to Yuta Nishie
    Guru 316760 points

    1. The test conditions are listed in the "test conditions" column.

    2. Under normal operation (VI = VCC or GND), ΔICC is zero, and the total ICC is the specified ICCA + ICCB.