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TPS7A87: TPS7A87

Adwait Deshpande
Prodigy 80 points
Part Number: TPS7A87
Other Parts Discussed in Thread: TLV752, TPS7A90, LM27761

Tool/software:

Hello, 

Subject: Can the LDO Provide Reliable Output for Load Currents Below 1 mA?

Part Number : TPS7A87

Part Number Description : Linear Voltage Regulator IC Positive Adjustable 2 Output 500mA 20-QFN (4x4).

In the datasheet of the LDO I'm considering, the output current (IOUT) is specified to range from 0 mA to 500 mA. However, there is no mention of the minimum load current requirement, and the datasheet does not include a graph showing the regulator's performance at low load currents. My application requires the LDO to operate reliably with a load current of less than 1 mA for CMOS image sensor application. Could you confirm whether this LDO can maintain stable operation at such low current levels, or provide any additional guidance or data regarding its performance under these conditions?

Thank you!

  • 0
    TI__Genius 13740 points

    Hello Adwait,

    There is no minimum current requirement for this LDO. This LDO can maintain stable operation at less than 1 mA current. The dropout voltage, noise, load regulation and quiescent current will be much lower at lower loads (better performance) but the efficiency will be reduced. 

    What is the end equipment for this application? What is the VIN, VOUT, Iq and noise requirement? Knowing this would help me suggest any alternative device options to you.

    Best Regards,

    Ishaan

  • 0 in reply to Ishaan Shetye
    Prodigy 80 points

    Thank you for your prompt response.

    As mentioned, this design is intended for a CMOS image sensor application with the following specific requirements:

    • Input Voltage (VIN): 5V
    • Output Voltage (VOUT): Adjustable, up to 3.5V
    • Noise Requirements: Ripple < 30 µV peak-to-peak
    • Quiescent Current (IQ): Should be kept low to optimize power efficiency
    • Minimum Load Current: Less than 1 mA

    Given these parameters, I am looking for an LDO that can maintain stable operation under these conditions. Additionally, if there is an IC available that includes multiple LDO outputs, that would be more suitable for my application.

    I appreciate your assistance and look forward to your recommendations.

    Thank you!

  • +1 in reply to Adwait Deshpande
    TI__Genius 13740 points

    TPS7A87 fits your specifications. TLV 751 is another dual output LDO which meets your specs. I would also consider TLV752 which is not dual output. This choice is application specific but we usually suggest cascading two LDOs for better thermals and enhanced PSRR. I would suggest using TPS7A87 if your application involves powering interdependent signal chain elements such as VCOs, ADCs, DACs, LVDSs or ASICs. 

  • 0 in reply to Ishaan Shetye
    Prodigy 80 points

    Thank you sir for your assistance, it has successfully resolved my issue.

  • 0 in reply to Ishaan Shetye
    Prodigy 80 points

    Another doubt is regarding Longevity and Suitability of TPS7A90 LDO for New Designs

    I am currently using the TPS7A90 LDO in one of my designs and would like to know if it is advisable to continue using this component for new designs. I noticed on the TI website that a newer version of this LDO is available. However, I have concerns because the noise (in RMS) for the newer LDO is more than 53µV, which is higher compared to the existing TPS7A90.

    Could you please provide guidance on the longevity of the TPS7A90 and whether it is recommended for new designs? Additionally, how does the increased noise in the newer LDO impact its performance compared to the TPS7A90?

  • +1 in reply to Adwait Deshpande
    TI__Genius 13740 points

    TPS7A90 is not being obsoleted and you can use it for new designs although we do recommend the newer alternatives. However, if noise is an important consideration for your application, I would go ahead with TPS7A90. Please note that it used a 10nF noise reduction capacitor to achieve the 4.7µV RMS noise figure. 

    The impact of the increased noise would be application specific. Please look at section 2 of each data sheet to determine where your application fits. Dropout, efficiency, power dissipation, Iq, line and load regulation are not significantly impacted by the increased noise.

  • 0 in reply to Ishaan Shetye
    Prodigy 80 points

    Subject: Seeking an LDO to Generate -0.7V @ -1.39mA and -0.7V @ -1.5mA

    I am looking for an LDO that can generate a negative voltage of -0.7V at currents of -1.39mA and -1.5mA. After searching through various options, I found the LM27761, which offers an output range of -1.5V to -5V.

    However, since this range does not include -0.7V, I am wondering if there is an alternative LDO that can directly provide -0.7V. If not, could you please advise on how I might achieve this voltage using the LM27761 or any other method?

  • 0 in reply to Adwait Deshpande
    TI__Genius 13740 points

    Hello Adwait,

    This is a very different topic from the thread you started above. Could you please either post this question in a new thread or contact ldo_industrial_marketing@list.ti.com OR ldo_auto_marketing@list.ti.com depending on your application?

    Thank You