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Automotive voltage level translation from 12V to 3.3V

Hello,

I have an automotive circuit with MSP430F5438A and there are some inputs to be given to the MSP from the automobile electronics.

All the inputs will have 12V and for MSP430, they need to be shifted to 3.3V. Also the current in those inputs can be pretty high, ranging from 500mA to 1 or 2A.

Is there any IC that could be used?

I have looked at TLC27L4, CD40109B-Q1.

Can anyone provide an expert opinion on which one to use? Also if any other solutions available??

 

1 Reply

  • Hi Shashank,

    Firstly I am not an expert, but I would suggest you the following:

    As you mentioned in your post the circuit is automotive I suggest to isolate you controller from the inputs. As I can see the high voltage and current ratings of 12V and 1Amps. I think you should got with two stages.

    1: Use resistor dividers to bring down your voltage to 5.0V and take care of current rating while designing your divider circuit.

    2: Use digital isolators with one side operating @5.0V and other side operating @3.3V, with lower voltage side connected to your controller.

    There are some other replacements of divider, that can be implemented using opamps if you want.

    Refer the thread:

    http://www.edaboard.com/thread217442.html

    Thanks and Regards

    -Anand