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Datasheet - SN65HVD232
Full part no - SN65HVD232D

My schematic -

enter image description here

Hi all, there is a problem in my PCB where 5V track is connected to VCC pin instead of 3.3V. Actual input should be 3.3V as per datasheet.

So will it work?

One more thing - pins 5 & 8 are NO CONNECT pins but I have 3.3V and a GPIO pin connected to them respectively (to be compatible with another transceiver IC).

Will that pose any problem?

Please help me with this. It is urgent.

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  • \$\begingroup\$ "No" means "no" and "no connect" means.... \$\endgroup\$
    – Andy aka
    Commented Dec 10, 2020 at 14:20
  • \$\begingroup\$ Get the scalpel out... and next time, make the NC connections via 0 ohm resistors so you can connect them for the alt part and leave them NC for this one. \$\endgroup\$
    – user16324
    Commented Dec 10, 2020 at 14:34
  • \$\begingroup\$ @Andyaka - huh? "no connect" usually means "not connected internally" or "it is okay to connect anything to these pins" \$\endgroup\$
    – ProPlayerMaxUltra
    Commented Dec 10, 2020 at 14:47
  • \$\begingroup\$ @BrianDrummond - yes next time i'll surely remember! \$\endgroup\$
    – ProPlayerMaxUltra
    Commented Dec 10, 2020 at 14:48
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    \$\begingroup\$ @MANI It depends. You must check datasheet \$\endgroup\$
    – DKNguyen
    Commented Dec 10, 2020 at 14:48

2 Answers 2

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It will be operating outside ratings. May work, may not. Behavior undefined. It may get hot and short your 5V.
Note that your logic levels will be 5V too, so this may damage the part that is connected to CAN1_TX and CAN1_RX.

See if you can replace it for a different part. Eg: TCAN1044
Many can tranceivers are pin compatible. Above mentioned has a Logic Vio, possibly at the right pin, to not damage CAN_TX/CAN_RX.

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  • \$\begingroup\$ Hot? No. Short? No again. IC is cool for like 10+ hours. My MCU is STM32F446RC whose pins are 5V tolerant. That might be the reason why MCU is still working. Yeah I chose MCP2562FD (same as TCAN1044) as alternate. VIO is missing in this particular part. So I should lift the pin up and place a jumper to 3.3V for assured behavior. \$\endgroup\$
    – ProPlayerMaxUltra
    Commented Dec 10, 2020 at 15:03
  • \$\begingroup\$ Not all pins on a STM32 are 5V tolerant, so check if the pins where you have the CAN is 5V tolerant or not. \$\endgroup\$
    – Justme
    Commented Dec 10, 2020 at 15:24
  • \$\begingroup\$ @Justme - checked. they are 5V tolerant. \$\endgroup\$
    – ProPlayerMaxUltra
    Commented Dec 10, 2020 at 15:29
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    \$\begingroup\$ @MANI pins are not 5V tolerant in all configurations. Check if TX is open drain. Else it isn't tolerant in push-pull. \$\endgroup\$
    – Jeroen3
    Commented Dec 11, 2020 at 16:03
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The NC pins are said to be not connected internally, so it should be safe but you must of course verify the operation. In some datasheets it is explicitly said if NC meand no connection and pin can be used for easier routing, or if pin is internally reserved and must have no connections. Sometimes this is indicated with DNC, Do Not Connect.

The 5V supply is out of recommended range, and the opetation is not guaranteed because of this. So some chips may work and some may not. The chip will also use 5V logic levels, which your other device may accept or it might get damaged because of it.

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  • \$\begingroup\$ +1 - thanks for the answer but most of this was already covered by Jeroen3. \$\endgroup\$
    – ProPlayerMaxUltra
    Commented Dec 10, 2020 at 15:17
  • \$\begingroup\$ It was mentioned that those pins are not connected internally and can be left floating. But they didn't tell what happens if something is connected. \$\endgroup\$
    – ProPlayerMaxUltra
    Commented Dec 10, 2020 at 15:18

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