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CA3078 Pin to Pin Replacement/Alternate

Harish Singh
Intellectual 995 points
Other Parts Discussed in Thread: TLV2471, OPA340, TLV271

Dear All,

CA3078 datasheet.pdf

We have a flowmeter amplifier product in which we use CA3078 IC originally from Intersil. Now since the IC is obsolete, it is becoming very tough to find the IC in the market.

I am not able to find the pin to pin alternate to CA3078 with frequency compensation pins, min 1Mhz bandwidth, low power and DIP-8 package availability.  

Does TI has any part that can replace pin to pin in our existing product?

Datasheet of CA3078 attached for reference.

Regards,

Harish KS

  • 0
    Guru 140200 points

    Hi Harish,

    what parameters of CA3078 are important for you? Or by other words, what paramteres should the TI's replacement have?

    Kai

  • 0 in reply to kai klaas69
    Intellectual 995 points

    Hi Kai,

    Thanks for the reply. We need

    1. pin to pin replacement to CA3078

    2. frequency compensation pins

    3. Rail to rail output

    4. min 1Mhz bandwidth

    5. Minimum supply voltage +3V

    6. low power

    7. DIP-8 package availability.  

    Regards,

    Harish KS

  • 0
    TI__Genius 10850 points

    Hi Harish,

    We do not have an equivalent amp with the frequency compensation pins. We can help you find an amp to do what you need, but we will not be able to get you that exact pin-out. Is that acceptable?

    -Tamara

  • 0 in reply to kai klaas69
    TI__Guru* 93105 points

    Hi Harish,

    The move from through-hole to surface mount technology has much diminished the demand for op amps in the PDIP package. Therefore, only a few TI op amps remain available in the 8-pin DIP. None that I am aware of are uncompensated versions. However, for the remaining compensated op amps available in the 8-pin DIP package, pins 1 and 8 have no internal connection so the external compensation capacitor used with the CA3078 would be automatically disconnected. That situation goes for the CA3078 pin 5, bias pin as well. That pin too is not commonly connected in most 8-pin DIP op amps. Therefore, the external bias function which probably isn't needed in most applications isn't available in modern 8-pin DIP op amps.

    Since your requirement is for 3 V minimum supply I am assuming the supply voltage is low, such as 5 V? If so, the OPA340PA would meet or exceed the electrical and package requirements in your list. The external frequency compensation and bias function of the CA3078 are not used with the OPA340PA, but then again I don't see why they would be needed if the replacement op amp meets or exceeds the performance of the former device.

    You can view the OPA340PA datasheet here:

    http://www.ti.com/lit/ds/symlink/opa340.pdf

    Regards, Thomas

    Precision Amplifiers Applications Engineering

  • 0 in reply to Thomas Kuehl
    Intellectual 995 points

    Hi  Thomas,

    Thanks for the detailed answer. I got your point. Yes, the supply is 5V only.

    I will check the existing pcbs with OPA340 and other ICs with the same pin-outs as TLV271 or TLV2471. I believe it should definitely work.

    Thanks & Regards,

    Harish KS