INA282 gain question

Hi Ren,

I received your question and will be reviewing tomorrow. 

Regards

Hi Red,

I just reviewed this schematic and this configuration is not recommended by us. INA internal resistors are precisely matched to meet offset and gain error specs. Adding external resistors in the input (greater than 10 ohms) will change the gain but it will come wit the costs of degraded offset and gain errors, which we can't guarantee. Adding external resistors to change the gain is not recommended. 

Regards,

Red,

Adding to Mayrim's comments, the 3k resistors can be eliminated if the power rating of the Zener diodes is sufficiently high. What is the maximum current output (i.e. current limit) of the supplies driving the HV/HVIN nets? Once that is known you should be able to search for protection diodes with power rating >= 75V x Ilimit.

Regards,

Harsha Munikoti

Hi Harsha& Mayrim

thanks a lot for kindly reply, for some reason, my customer would not change the design since this is automotive application,

however, after did some experiments, add 3Kohm will bring some offset, the variation is around 10%, customer will try to use calibration to cover that,

my question, may i have your help to give me the tolerance of input impedance?

the typ is 3Kohm we need to know the max and min values

thanks a lot