• State TI Thinks Resolved
  • Locked Locked
  • Replies 6 replies
  • Answers 1 answer
  • Subscribers 50 subscribers
  • Views 293 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

LMH6554: Negative voltage supply device recommendation

JH Shin
Mastermind 8180 points
Part Number: LMH6554

Hello,

My customer is planning to use the LMH6554 for ADC input driver application.

So, they are looking for a low noise, negative-voltage device with the following conditions

    - VIN = +12V or +2.5V, VOUT = -2.5V, IOUT = 0.5A

Could you please recommend a negagive voltage supply for LMH6554?

Thank you.

JH

  • 0
    Guru 140200 points

    Hi Jh,

    hhm, your specifications are confusing me. An ADC which consumes 0.5A input current? This is not in the reach of LMH6554.

    Can you show a schematic? Or at least tell what ADC we are talking about?

    Too high input voltages could be sized down by a resistive voltage divider. And the maximum supply voltage between the supply voltage pins of LMH6554 is 5.5V. That's all I can say at this moment.

    Kai

  • 0
    TI__Expert 3620 points

    Hi JH,

    I think this is more of a power design question than an amplifiers question, but Kai makes a good point. Is the 500mA requirement due to this needing to supply multiple devices? Sometimes smaller single purpose supplies can use a charge pump or negative reference, but this amount of current output will require a switch mode power supply with a large inductor. Would you like me to forward this to the power design team?

    Best,
    Sam

  • 0 in reply to Sam Burnett
    Mastermind 8180 points

    Hi Sam,

    Thanks for your reply.

    The customer said that they use two LMH6554 and need negative power solution for V- of the LMH6554.

    They considered design margins according to the efficiency and environment condition.
    If there is no problem with using a device with a smaller current capacity for the two LMH6554, the current specification can be ignored.

    Please recommend a suitable negative power supply device.

    Regards,

    JH

  • 0 in reply to JH Shin
    TI__Mastermind 24095 points

    Hello JH,

      What power supply configuration will the customer use for the LMH6554 at VS+ and VS-?

       As Kai and Sam mentioned, the max +/- power supplies is 5.5V. An input between +/2.5V to 12V will be too high for the device without using an attenuator at the input of the LMH6554. 

    Thank you,

    Sima 

  • 0 in reply to SimaJalaleddine
    Mastermind 8180 points

    Hello Sima,

    Sorry for the confusion.

    My customer wants a product recommendation for suitable TI power devices(for example DC/DC or LDO devices) for supplying the V-power of the LMH6554.

    They use the LMH6554 for noise sensitive ADC input circuit, so they want to use the solution recommended by TI.

    Thanks,

    JH

  • 0
    TI__Expert 3620 points

    Hi JH,

    There are a ton of options here, so I would do a parametric search on Buck-boost & inverting regulators product selection | TI.com for one of our inverting switchers.

    I have also had success in the past using the Webench power design tool, which can help you implement your chosen  SMPS with the proper inductor, etc.

    WEBENCH® Power Designer | Overview | Design Resources | TI.com

    You can specify the system requirements, performance specs (ripple, etc.) and even add EMI filtering. It will also let you specify component considerations like shielded inductors.

    If you require expert assistance with the design I can forward this post to the power design team as I stated previously.


    Best,

    Sam