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TPS7B86-Q1: my product is resetting in BCI testing @ 100mA in frequency range of 10MHz to 50MHz

Anuj Garg
Prodigy 10 points
Part Number: TPS7B86-Q1

Tool/software:

we are using 2 LDOs of TPS7B8601QDDARQ1 in supply line of our product. While conducting the BCI testing at 100mA, the product become OFF or reset between the frequency range of 10MHz to 50MHz. but in between

50MHz to 400MHz, it works ok.

The output current at 5V is 100mA max. and at Vin is 300mA max. Please suggest improvements to qualify it in BCI testing. 

  • 0
    TI__Genius 13460 points

    Hi,

    I'm reviewing your request and will get back to you with a preliminary response in 2 business days

    Regards

    Ishaan

  • 0 in reply to Ishaan Shetye
    TI__Genius 13460 points

    Hi Anuj,

    Another engineer from your company, Kapeesh Kumar had posted on a similar issue. Is this the same BCI test for the same application? Please check with him for the comments I gave. 

    To summarize:

    • Place decoupling capacitors as close as possible to input pins
    • Use multiple decoupling capacitors in parallel (1uF OR 10 uF + 0.1uF + 0.01uF) depending on the Frequency range of the test to suppress noise on the VIN pin.
    • You can add a feedforward capacitor (Cff) on the LDO to suppress noise and pass the HF injection
    • Reduce the number of vias, merge GND together and keep the plane pour as large as possible.
    • Please check if the input filter you are using is not acting as a bandpass. You want to filter out HF so make sure the cutoff frequency is less than 10 MHz

    Regards

    Ishaan

  • 0 in reply to Ishaan Shetye
    Prodigy 10 points

    please share the schematic with required value of each component to prevent the reported issue during BCI testing

    also, please share the PCB layout guideline document with examples for this part

  • 0 in reply to Anuj Garg
    TI__Genius 13460 points

    Hi Anuj,

    We have this resource available for Pi filter design: Input Filter Design for Switching Power Supplies. For linear supplies, an LC filter will work just fine. You can use our filter design resource here: Filter Design Tool

    Layout guide for this part is shown on page 29 of the datasheet.