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ONET4291T: Low frequency and DC operation

Part Number: ONET4291T
Other Parts Discussed in Thread: OPA857-DIE

I am looking for information to know if the ONET4291T TIA works down to DC or has a frequency floor. I need an amplifier that is in die packaging and works down to DC for amplifying a small siginal from an InGaAs detector.

Am currently looking into the ONET4291T, but if that does not go to DC what is a recommended product for the application.

Thank you in advance for the help.

  • Hi Evan,

    As shown in Figure 1, the ONET4291T has an input DC current bias cancellation circuit. This means that DC coupling is not supported. The lower frequency is around 50kHz.

    I will need to check to see what other TIA amplifiers we have in die form.

    What is your bandwidth requirement? What is your diode junction capacitance? What gain do you require?

  • Thank you for the fast reply Loren.

    Our bandwidth is rather low. We are currently using a AD8015 (See attached data sheet) AD8015.pdf and would like to replace it with something similar that is not so close to end of life. We would also like to reduce the noise as well.
    We are looking into the OPA857-DIE.

    I am not sure on the junction capacitance but I will ask some other engineers on my end to find out.