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AD825 Transimpedance Configuration

I connected the AD825 in the following Configuration

Supply: Single Ended 12 V and Ground

Non-Inverting Pin: 5V DC to shift the output voltage level to a positive level

Inverting Pin: 100 micro Ampere Current from Keithley Current Source

Gain Resistor: 3.2K Ohms

However, once I turn on the supply, the op-amp gets instantly heated up. I had 2 of these op amps that failed in the same manner. Am I missing something here ? Kindly Help

Parents
  • Hi,

    Are you using evaluation board,  bread board or vector board on your setup?

    Where did you connect the other end of the current source? is it on the ground? Can you try to connect it on the 5V also and see if there is any difference?

    Can you confirm that the gain resistor is connected between out and inverting pin?

    Also, what is the load connected at the output of the amplifier?

    Best regards,

    Emman

Reply
  • Hi,

    Are you using evaluation board,  bread board or vector board on your setup?

    Where did you connect the other end of the current source? is it on the ground? Can you try to connect it on the 5V also and see if there is any difference?

    Can you confirm that the gain resistor is connected between out and inverting pin?

    Also, what is the load connected at the output of the amplifier?

    Best regards,

    Emman

Children
  • Hi Emman,

    The setup is built on a breadboard.
    The other end of the current source is connected to the ground.
    I did try giving a 5V supply and designing an inverting amplifier to check the functionality, but the amplifier isn't responding. I believe it broke down when I gave a 12 V supply to it. Kinda heated up pretty fast

    I can confirm that the gain resistor is connected to the inverting pin and the output pin. 
    I did not connect any load resistance at the output. I tried measuring the output directly from the pin with a fluke 287 MULTIMETER. Should I connect a load resistor and measure across it?

    Thanks for your time

  • Hi Harihan,

    You should be okay to measure the output directly using the fluke multimeter.

    This part should be able to operate in 12V single supply even up to 30V.

    One thing that you can damage the parts is when you violate the absolute maximum rating as shown on page 12 of its datasheet. One possible scenario is when you apply the 5V first before the 12V power supply.

    Do you have new working parts that you can try and be aware of the power sequence as well as double check all the connections of your circuit before powering up the device.

    Best regards,

    Emman

  • Hi Emman,

    I did look into the absolute maximum ratings before connecting the circuit. Also, I did verify that the power supply gave me a 12.2 V out before connecting it to the circuit.

    In addition, I also applied a 5V DC to the non-inverting pin to clamp my output to positive levels. I had 2 ICs and both faced the same problem.

     I will see if I can order it again and try the experiment one more time.

    Thank you for your time.
    Hariharan V