• TI Thinks Resolved


Part Number: LM2576

Dear Employer,

I am using LM2576S-5.0/NOPB to convert 24V to 5V.

The output current of switcher is 3A,But What is the Maximum input current capacity?

In my case the input current will be 24V@5A Will it cause any damage?


Mit Shah

  • Mit Shah,

    5V_OUT at 3A_OUT will probably draw no more than 780mA_IN unless the efficiency is very poor.

    5V_OUT at 3A_OUT will get you 15W_OUT.
    24V_IN at 15W_IN will get you 625mA_IN in (assuming 100% efficiency). This will be ~780mA_IN due to ~80% efficiency.

    We do not specify input current because you can calculate it using VIN, VOUT, IOUT, and efficiency.

    24V_IN at 5A_IN would be 120W_IN. If you have 120W_IN and 15W_OUT, that means 105W is dissipated as heat in the board which will not happen in normal operation. Your board, if operating properly, will automatically draw the appropriate amount of input current (~780mA) if you have 24V_IN, 5V_OUT, and 3A_OUT.