ADA4075 Differential Input Voltage

Hi mehran,

mehran said:

What does this mean?

This amplifier has diode protection between the inputs and if the differential input voltage is sufficient to directly bias these diodes, a significant current will flow through the inputs, which should be limited to a safe level.

mehran said:

how can I consider it in my design?

To get started, please share your design diagram

Regards,

Kirill

Thanks for your answer 
This is what I designed and tested with ADA4075 practically. Also in the datasheet, the maximum common-mode voltage has been not defined, please also help me with it.

Hi mehran,

It should be clear that you are using a differential configuration, here the differential input voltage of the circuit is not equal to the voltage between the inputs of the op amp and can significantly exceed it. Due to the action of negative feedback, the voltage between the inputs of the op amp is close to zero.

If I understand correctly, you are using a supply voltage lower than +/- 15 V and you are interested in the allowable range of common-mode input voltages. For the + / - 5 V case, you can extract useful information from this graph

Common-mode voltage can be + / - 3 V. This is 2 volts lower than the supply voltage, and in the case of a supply voltage of + / - 15 V, the common-mode voltage is 2.5 V lower. Focus on these numbers.

Regards,

Kirill

Hi mehran,

It should be clear that you are using a differential configuration, here the differential input voltage of the circuit is not equal to the voltage between the inputs of the op amp and can significantly exceed it. Due to the action of negative feedback, the voltage between the inputs of the op amp is close to zero.

If I understand correctly, you are using a supply voltage lower than +/- 15 V and you are interested in the allowable range of common-mode input voltages. For the + / - 5 V case, you can extract useful information from this graph

Common-mode voltage can be + / - 3 V. This is 2 volts lower than the supply voltage, and in the case of a supply voltage of + / - 15 V, the common-mode voltage is 2.5 V lower. Focus on these numbers.

Regards,

Kirill

Thank you, Kirill.
Now it is clear for me and It is really useful.