ISO1212: Can this part sink or source current with a single front end circuit?

Lauren Mayfield

Part Number: ISO1212

About this part - I understand it can either source or sink current but it will require an slightly different front end circuit.

Can ISO1212 can sink or source current with a single front end circuit?

over 3 years ago

0 Manuel Chavez over 3 years ago

TI__Genius 17100 points

Hi Lauren,

A bidirectional front end can be configured using one of the circuits described in Section 9.2.3 of the ISO121x Datasheet as shown below:

Are either of these circuits acceptable?

Thank you,
Manuel Chavez

0 Lauren Mayfield over 3 years ago in reply to Manuel Chavez

TI__Expert 6910 points

Hi Manuel,

Thanks for your reply.

We will use the circuit in figure 30 for each input. We only have 3 pins input connector: 2 input signals and a

common for both inputs. So I wouldn’t be able to make both inputs bidirectional due to number of pins constraint.

Therefore, is it safe to say that either both inputs need to source or sink current?

0 Lucas Schulte9 over 3 years ago in reply to Lauren Mayfield

TI__Expert 6955 points

Lauren,

If you set up the ISO121x like in figure 30, then the device's inputs will be sinking current since that is the only direction current can flow due to the diodes. I'm not sure if this answers your question though. Can you provide a figure or diagram to better illustrate what it is you are asking?

Respectfully,

Lucas

0 Lauren Mayfield over 3 years ago in reply to Lucas Schulte9

TI__Expert 6910 points

We have two channel inputs with following pin assignments: IN1 , IN2 , COM. That’s is total of 3 pins.

I just want to confirm that I wouldn’t be able to configure 2 channels to be bidirectional since I have only

one common input.

0 Lucas Schulte9 over 3 years ago in reply to Lauren Mayfield

TI__Expert 6955 points

Lauren,

You are correct in your assumption. The singular common would prevent this. That being said, both inputs of the ISO1212 would then be sinking current.

Respectfully,

Lucas

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ISO1212: Can this part sink or source current with a single front end circuit?