LT1819 not responding

Hi,

Is it possible for you to post your schematic?
It would help us to check other possible components that may cause the issue.

Thanks and regards!

Hi,

I'm not sure how will you have 4.096V as an output.

Based from your circuit, the output of the LT6275 is 0.00004 * 4.7k = 188mV.
The output of the U1 LT1819 = 188mV [1 + (1.33k/50k)] = 193mV.
The output of U2 LT1819 = 193mV [10k / (5k + 10k)] = 129mV.

That is the expected output based from your circuit.

Thanks and regards!

Correct. am sweeping input current from LT6275 from 0.04mA to 1.2mA

am getting some output but it is toggle - 200 to 500mV noise is there

Hi,

When using single supply of 5V/GND, your minimum input is limited to 1.5V and 800mV typical.
Thus, the part will not accept input lower than this values.

I suggest you pick op-amps with rail-to-rail input and rail-to-rail output.
Else, use a split supply with 10V range (e.g. -3.5/+6.5V).

Thanks and regards!

Hi If I try negative voltage opamp got heated

even if I give -1V also it is heating. can you suggest any

Hello,

Do you mean negative voltage at the supply?
This should not be an issue.

If using single supply(e.g. 5V/GND), does your part heats up?

I think your part might be already damaged.

Thanks and regards!

Single 0 to 5v it is not heating. If I change negative supply it is heating

Single supply is working good. But output range is 0.5 to 4.5v. I need 0- 4.5 v

Hi,

Can you try 10V/GND on your supply and check if there is a heating issue.

Thanks and regards!

Not heating for 0 to 9V

Hi,

Since you are also seeing oscillation as you have mentioned (-200mV to 500mV), please consider using feedback capacitor along with your feedback resistor (R3) at U1.
The Cf value is obtained by the equation: CF > RG • CIN/RF

Also, the U2 is driving 10nF Cap load.
Please use isolation resistor value of 10 to 50 ohms as recommended by the data sheet.

And the least thing, if you are open on using fresh unit to check if you will have the same performance as what you have now.
In addition, please use supply voltage of 10V only.

Thanks and regards!

Hi,

Since you are also seeing oscillation as you have mentioned (-200mV to 500mV), please consider using feedback capacitor along with your feedback resistor (R3) at U1.
The Cf value is obtained by the equation: CF > RG • CIN/RF

Also, the U2 is driving 10nF Cap load.
Please use isolation resistor value of 10 to 50 ohms as recommended by the data sheet.

And the least thing, if you are open on using fresh unit to check if you will have the same performance as what you have now.
In addition, please use supply voltage of 10V only.

Thanks and regards!