At the beginning of the measuring task, I mixed up wires connecting my FTDI USB to UART cable (TTL-232R-3V3) with serial connector header pins (TX/RX/VCC/Gnd) on device (data modem). I didn't immediately noticed the error, just after ~4-5min, after discovered the smell of hot plastic. As a result, the FTDI cable connection header got very hot. How can I make sure that I haven't damaged the laptop's motherboard and the FTDI chip itself? I tried then connect with correct pins, it works and show output. Nevertheless, the cable header was extremely hot. Sure, this FTDI cable is not a MIL standard, what max temperature it can hold? Can I be sure that FTDI chip with its other components and laptop motherboard are fine?

Absolute maximum ratings for FT232R device are as follows:

enter image description here

  • \$\begingroup\$ extremely hot means a different thing to different people ... you are basing your question on some unknown quantity \$\endgroup\$
    – jsotola
    Oct 15, 2021 at 0:30
  • 3
    \$\begingroup\$ There is no way to guess if anything is degraded or damaged and if something is damaged, there is no estimate how much and in which units. \$\endgroup\$
    – Justme
    Oct 15, 2021 at 0:33

1 Answer 1


As @Justme commented, there is no way to tell if something is damaged. Just because you can see output from the device, this does not guarantee that it is intact.

Most (if not all) datasheets from ICs, they mention somewhere "Absolute maximum values" of voltage, temerature and current. For example this datahseet from Si826x mosfet gate drivers:

absolute maximum

Along with that, they mention that the device might undergo permanent (internal) changes/ damage beyond repair, if these maximum ratings get violated, you device might get damaged (and you may not notice it). damage beyond maximum ratrings

For example there can be a "hole" (aka burn) inside a transistor, caused by the high current, which causes the transistor to draw more current (so getting a little bit more hot), but still work as good as before.

Example of a hole inside a mosfet:

hole mosfet transistor


Since your devices got "so hot" (while they are not supposed to), this means some of the maximum ratings were violated. If you want to do a professional work, you should replace and NOT use all the devices that got hot.

  • 1
    \$\begingroup\$ +1 for "If you want to do a professional work, you should replace and NOT use all the devices that got hot." I had a serial cable here which also someone plugged wrong and the header melted. It kinda worked afterwards, but kept freezing. \$\endgroup\$
    – akwky
    Oct 15, 2021 at 7:57
  • \$\begingroup\$ Yes. I learned that from work. Anything that seemed a bit off or resulted in errors we throw it away (or use it for prototyping/testing) and never use it in out machines. Once I short circuited a PCB with the oscilloscope probe while testing it on the oscilloscope. (I shorted the 5V line to gnd when removing the oscilloscope probe). We changed the PCB (and a second pcb that is connected to it), the power supply, the fan of the machine. Even though they work fine, I keep them for testing/prototyping. \$\endgroup\$ Oct 15, 2021 at 8:51
  • \$\begingroup\$ "hot" means hot - this is consumer electronic, not a MIL-STD electronics. \$\endgroup\$
    – minto
    Oct 16, 2021 at 11:45

Not the answer you're looking for? Browse other questions tagged or ask your own question.