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CAN Tranceiver 3.3V
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lollandster:
Hi,
I' working on a simple CAN transmitter for interfacing between various sensors and a datalogger (no car is involved). The design will be based around a STM32F103 (at least that is where I started).
My question is about voltage levels.

Most transceivers I've found need a 5V power supply. Since the STM32 is 3.3V, this isn't ideal. I've found several transceivers that claims to work on 3.3V, but all of them have a lower output voltage than the 5V transceivers.
Does anyone have experience with 3.3V based CAN transceivers? I'm thinking TCAN332G for my design.
Niklas:
The CAN Tx and Rx pins on the STM32F103 are 5V compatible so you can connect a 5V transceiver directly to them. Another option is to use a transceiver with a separate supply for the logical interface. Look for a Vio pin and connect your 3.3 V supply there.
lollandster:

--- Quote from: Niklas on June 06, 2019, 11:46:55 am ---The CAN Tx and Rx pins on the STM32F103 are 5V compatible so you can connect a 5V transceiver directly to them. Another option is to use a transceiver with a separate supply for the logical interface. Look for a Vio pin and connect your 3.3 V supply there.

--- End quote ---
That isn't the issue. I don't want to have a regulated 5V supply.

I did find some more information about 3.3V compatibility from Linear Technologies. It looks like it shouldn't be an issue.
https://www.analog.com/en/technical-articles/can-bus-transceivers-operate-from-33v-or-5v-and-withstand-60v-faults.html
Rerouter:
the issue is the bus active state, the can high line needs to go above 3.3V, so unless the device has an internal boost converter it needs to have a higher supply, you cant get away with using a simple bucket-brigade 3.3-5V regulator?, no complex inductor stuff involved. just a single capacitor and an IC.
lollandster:

--- Quote from: Rerouter on June 06, 2019, 11:56:57 am ---the issue is the bus active state, the can high line needs to go above 3.3V, so unless the device has an internal boost converter it needs to have a higher supply, you cant get away with using a simple bucket-brigade 3.3-5V regulator?, no complex inductor stuff involved. just a single capacitor and an IC.

--- End quote ---
So why do Texas Instrument, Linear Technology and Maxim Integrated sell 3.3V CAN transceivers? It clearly works. I'm just wondering if there are issues related to doing so.
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