INA199: 3.3V supply current @ 3.6A current on 7mohm Rsense design

Hello Ann,

There will be more information needed to better model the supply current drawn by the INA, mainly the output current that the INA will supply. For this we need to know what is connected to the output of the INA. Also the customer should check if the INA can supply the current required. This can be checked by using the "claw graphs" seen in Figure 6.

This is not all the supply current, once the output current is determined we must add the quiescent current to it. This can be found in the datasheet under table 7.5 in the power supply section.

If you have any other questions please reply

Regards,

Castrense

Hello Castrense,

We would like to know the supply current, not the output current. May we know if you have supply current could be reference? Thanks a lot!

Best regards,

Ann Lien

Hi Ann_Lien,

the supply current should be sub mA.

What is the load resistance at the output of INA199? The output load current might dominate the quiescent current of INA199.

Kai

Hello Ann and Kai,

I must not have explained myself well. Let me try again. You have asked for the supply current during operation while a current is being measured on the input, because of this I assume you are interested in monitoring the output voltage of the INA. If there is anything connected to the output of the INA with resistance the INA will supply an output current. This output current will be sourced from the supply pin of the INA. 

The INA will also have a current it will use when the output is zero which is the quiescent current, which is specified in the datasheet. 

If we add the output current the INA will supply in your application plus the quiescent current the INA consumes we can have an idea of the supply current.

If you have any questions please reply

Regards,

Castrense

Hello Castrense,

Customer would like to know how many power budget they need to place for INA199 for 3.3V supply voltage. So output current should be the same as supply current(ignore quiescent current), right? If yes, we can use output current to estimate. Thanks!

Best regards,

Ann Lien

Hello Ann,

Yes this will be an estimate. 

Regards,

Castrense