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OPA455: Parameter requirement confirmation

Rhea Gao
Expert 2350 points
Part Number: OPA455
Other Parts Discussed in Thread: OPA445, OPA593, OPA462

Hi，

The customer has a new requirement that requires the voltage swing rate to be 40V/us and the OPA455 to be 32V /µs, but would like to know whether it can be used. Or please help to recommend compatible products.

Many thanks!

  • 0
    TI__Guru 54576 points

    HI Rhea,

    The OPA445 slew rate is 32V/µs typical for a 80V step.  Figures 6-43, 6-44 and 6-45 show the slew rate vs output step and slew rate vs supply in the inverting and non-inverting configuration.

    We offer other high voltage devices with faster slew rate, but the max supply supported is less than 150V:

    - For example, the OPA593 supports 85V supply with 45V/μs slew rate.

    - There are other devices with higher slew-rate although the supply capability is less than <150V.

    Questions:

    Does the application require the high voltage 150V supply capability?

    What is the output swing step requirement in the application, and how fast to they need to settle? 

    Please let us know the max voltage supply, bandwidth or any other key requirements in the application.

    Thank you

    Luis  

  • 0 in reply to Luis Chioye
    Expert 2350 points

    Hi Luis,

    1. The customer needs more than 100V power supply, SR ±40 to ±60V/us, the maximum 60V/us requirements must be met, bandwidth is a few megabits, need rail to rail.

    Luis Chioye said:

    Does the application require the high voltage 150V supply capability?

    What is the output swing step requirement in the application, and how fast to they need to settle? 

    Please let us know the max voltage supply, bandwidth or any other key requirements in the application.

    2.  But I have looked for all the products, but nothing can meet this need.

     Please help to suggest, will there be any product planning in the future?

    3. The customer has a problem he wants to confirm.

    The customer knew that ADI 6090-5 marked the maximum and minimum SR values, and when the minimum values did not meet the requirements, the customer replied that the product needed to be screened, and not all the products could meet the requirements.

    It only indicates a typical value of 32V/us, without the minimum value. Does it work like this? (And ADI's feedback seems to make no sense).

    Many Thanks!

  • 0 in reply to Rhea Gao
    TI__Guru 54576 points

    Hi Rhea,

    Regarding your questions,

    Rhea Gao said:
    1. The customer needs more than 100V power supply, SR ±40 to ±60V/us, the maximum 60V/us requirements must be met, bandwidth is a few megabits, need rail to rail.

    Unfortunately, as you have mentioned, we currently do not offer any amplifier supporting supply => 100V and high slew rate of 40 to 60V/μs slew rate. I currently do not have a device available meeting 100V power supply, SR ±40 to ±60V/us. The OPA593 supports 45V/μs slew rate but maximum supply at 85V and the OPA445, OPA462 support the higher 150V and 180V supply, but slew rate is limited to 32V/μs.

    Rhea Gao said:

    The customer knew that ADI 6090-5 marked the maximum and minimum SR values, and when the minimum values did not meet the requirements, the customer replied that the product needed to be screened, and not all the products could meet the requirements.

    It only indicates a typical value of 32V/us, without the minimum value. Does it work like this? (And ADI's feedback seems to make no sense).

    In general, it is not uncommon for amplifier's datasheets to only offer a typical value for the slew rate, and not offer a minimum specification.  The slew-rate of the amplifier is typically a function of the input stage bias current, and the slew rate can vary with temperature, device, and lot-to-lot variation.  A conservative guideline is to allow ±30% from typical on untrimmed devices.  

    That said, I can't comment on devices from other manufacturers.

    Thank you and Regards,

    Luis