ISO124: Circuit checking!!

Paul Yeh

Genius 13605 points

Part Number: ISO124
Other Parts Discussed in Thread: AMC1411, ISO224

Hi team,

Can you help to check is this circuit design ok or not?

Thanks

over 2 years ago

0 Tom Hendrick over 2 years ago

TI__Guru**** 168425 points

Hi Paul,

No, I'm sorry but this will not work. The ISO124 needs two bipolar supplies for the input and output stages and those need to be 4.5V minimum. The -Vsx cannot be tied to ground. If this is a new design and you need the wider spacing provided by the ISO124 package, I suggest you take a look at the AMC1411. The AMC1411 can operate from 3.3V on each side of the isolation barrier

0 Paul Yeh over 2 years ago in reply to Tom Hendrick

TI__Genius 13605 points

Hi Tom,

Customer changed solution and please help to double check!.

Thanks

0 Gerhard Kreuzer over 2 years ago

Expert 2580 points

Hi Paul,

correct, the ISO124 works nice with +-12V supply .... there were newer chips around. ISO224, for instance.

I replaced ISO 124 by ISO224, great success. And I has to feed a 24 Bit ADC with differential input

With best regards

Gerhard

0 Tom Hendrick over 2 years ago in reply to Paul Yeh

TI__Guru**** 168425 points

Hi Paul,

Assuming VNEG is 0V relative to pin 8, that you have proper bypass somewhere on the board, and your input voltage does not exceed the limits of the AMC1411, this looks fine.

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ISO124: Circuit checking!!