ISO124: ISO124 phase reversal

Lin_Charles

Part Number: ISO124
Other Parts Discussed in Thread: ISO224

Hi team,

My customer is using ISO124, they are curious about if this device supports the "No phase reversal" feature? How about ISO224? Thanks.

over 4 years ago

0 Alexander Smith over 4 years ago

TI__Mastermind 47625 points

Hi Charles,

I am not sure what this feature is. Do you have additional information? Is your customer asking if they are inverting op-amps?

There is some propagation delay, but they are not inverting.

0 Lin_Charles over 4 years ago in reply to Alexander Smith

TI__Expert 4260 points

Hi Alex,

Thank you for your help here. You can see the definition of phase reversal below. Customer is worried about below condition, when VS1 = VS2 = ±15 V and the input voltage higher than 15V, what will happened to the output? Thanks.

"Phase reversal is a condition that may occur with op amps and instrumentation amplifiers when the applied input common mode voltage approaches a voltage outside of the specified common mode voltage range. At that point the output slams to the opposite rail. It appears when the input pins were reversed."

0 Alexander Smith over 4 years ago in reply to Lin_Charles

TI__Mastermind 47625 points

Hi Charles,

Ah I see now.

I do not think this will be an issue since these devices are not op amps or instrumentation amplifiers. They are really delta-sigma modulators with a filter on the low side of the device. Please see this video for further information on basic device structure: https://training.ti.com/introduction-isolated-amplifiers

Under the described conditions I would expect the output to clip, not reverse. Additionally, the ISO124 will require some headroom from the voltage rails ~2.5V to operate without clipping.

0 Lin_Charles over 4 years ago in reply to Alexander Smith

TI__Expert 4260 points

Hi Alex，

Thank you for your help here.

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ISO124: ISO124 phase reversal