AMC3302-Q1: Why isolation amplifier AMC3302 (for current sensing) has low input resistance compared to AMC3330 (for voltage sensing)

Hi Srinivasa,

These devices have different input ranges. Is there a specific concern or reason for this question? Please let me know if you can share the background.

Best regards,

Eva

Hello Eva

Yes, I want to use AMC3330 for Current Sensor Application. Gain and Input voltage to AMC3330, I can manage but I want to know How differential input resistance is going to affect the application in detail as my application is critical.

I know there are specific isolation amplifiers are available for current sensing application but due to some other priority reasons I want to know. Please explain.

Hi Srinivasa,

What is your application? What does your signal chain look like? I think the calculations in this current sensing EVM user's guide may be useful to reference Section 4.1.3:

AMC-AMP-50A-EVM Evaluation board | TI.com

Best regards,

Eva

Hello Eva

My main doubt is:

Typical Input Resistance:

AMC3330-Q1: 1.2 Giga Ohm

AMC3302-Q1: 4.9 kilo Ohm

Please provide with some detailed information about the difference in the differential input resistance between them.

Hi Srinivasa,

I can look into this more. What detailed information are you looking for? 

Best regards,

Eva