LMP7721:

Hi,

yes, will work :-)

Having said this, don't forget to use guarding and clean the printed circuit board very thoroughly.

Do you want to post a schematic?

Kai

You will get more dynamic range using a decompensated device like the LMP7717, 

There is a section in this article on transimpedance design - no way to pursue this query without a source capacitance number. The end of this article includes tables of parts applicable to this. 

Yes post me a schematic for measuring current range from  0.5nA to 1mA using LMP7721

Thank you for your concern time and for your reply

LMP7721 ic will measure current range from 0.5nA to 100uA as transimpedence Amplifier ?

Can you suggest any Schematic Diagram or application diagram for Transimpedeence Amplifier for measuring current range of 0.5nA to 100uA using LMP7721

Hi shanmugapriyan,

can you tell more about your application? Where is the current coming from you want to measure? Is it DC current or AC?

Kai

Hi shanmugapriyan,

As Kai and Michael suggested, there are numerous TIA examples over our website. Enclosed are couple examples. 

https://www.ti.com/lit/an/sboa220a/sboa220a.pdf?ts=1610387349613&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FLMP7721%253FkeyMatch%253DLMP7721%2BEVM%2526tisearch%253DSearch-EN-everything

https://www.ti.com/lit/ug/tidu535/tidu535.pdf?ts=1610387639729&ref_url=https%253A%252F%252Fwww.google.com%252F

https://www.ti.com/product/LMP7721?keyMatch=LMP7721%20EVM&tisearch=Search-EN-everything#tech-docs

If you need further assistant, please provide us the design or application requirements, and we may be able to simulate one for you.  

Best,

Raymond

And a transimpedance design tool recently added by Hasan, over in the column of FAQ in the amplifiers landing page e2e, and again, can't do anything without

1. source capacitance,

2. desired closed loop BW

3. maybe some noise targets, 

HI,

I'm getting current range (0.5nA to 100uA) from potentiostat(Voltammetry). 

by due to chemical variation on solution current output will generated, for the above range and  I need to measure that current range using LMP7721 IC .

so LMP7721 IC will able to measure that current range or not?

Hi shanmugapriyan,

Q: so LMP7721 IC will able to measure that current range or not?

Yes, LMP7721 is able measure the current range from 0.5nA to 100uA for potentiostat application (Kai also replied to this question in his initial reply). The op amp is specifically designed for the type of applications. 

When using LMP7721, you will need to care about its operating conditions since the op amp has extreme low input bias current at +/-3fA. 

1.  The PCB is required to be operated in extreme clean environment. It is important to clean an assembled PCB in an ultrasonic bath to remove unwanted contamination, such as finger prints, residual flux, dust particles etc.. 

2. Keep the moisture away from the PCB. The board needs to be stored in a desiccant jar or sealed bag when it is not in use. After the ultrasonic bath, it is recommended to bake the PCB in a drying oven at 60-70C for 6-8 hours. This is to remove the excessive moisture absorbed by the PCB or molding compounds. pA leakage current at the input of LMP7721 op amp circuit may degrade your redox measurements.

Enclosed is the AN-1852 application report for designing pH electrodes. 

https://www.ti.com/lit/an/snoa529a/snoa529a.pdf?ts=1610463107648&ref_url=https%253A%252F%252Fwww.google.com%252F

If you have other questions, please let us know. 

Best,

Raymond

Hi Shanmugapriyan,

does it work?

Kai