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TPS563200: Asking for the recommendation on TPS563200 ripple noise design

SHH
Mastermind 32176 points
Part Number: TPS563200

Hi Team,

customer measured TPS563200 Step-Down Regulator ripple peak to peak 236mV very big. Customer have try measured other project board the same TPS563200 ripple peak to peak 64mV small, Can you help me to solve this problem?  

 

Would you please review and provide your comments?

Here is the schematic and ripple measurement.

 

 

BR,

SHH

  • 0
    TI__Guru**** 191445 points

    SHH,

    It may be a combination of measuring technique load current and poor ground layout.  Accurate ripple measurement requires that you measure directly across the output capacitors using a very short GND pigtail less than 1 cm, or preferably "tip and ring" method.  This should eliminate the HF noise on your measurement.

    Alos, it appears you are operating in eco-mode.  Ripple will always be higher in eco-mode.

    It is important to connect the input capacitors directly across the VIN and GND pins.  This will require routing the SW node etch on the back side or internal layer.  See the datasheet for layout guidelines.

  • 0 in reply to JohnTucker
    TI__Mastermind 32176 points

    Hi John,

    Customer saw TI suggestion layout input capacitor need to direct connect to TPS563200 1 and 3 pin. 

    they had tried Input capacitor to connect TPS563200 1 and 3pin, but noise peak to peak the same to big 256mV.

    Do you have any comment for improving this noise?

    BR,

    SHH

  • 0 in reply to SHH
    TI__Genius 10070 points

    Hi SHH,

    This noise is caused by your measurement, please set the bandwidth of the oscilloscope to 20MHz, and measure the ripple as John said.

    BR,

    Shawn

  • 0 in reply to Shawn Nie
    TI__Intellectual 1155 points

    HI Shawn,

    customer still have questions regarding TPS563200, they changed components find output side bead affect peak to peak ripple, The peak to peak ripple is 88mV. 

    See below pics, the question is why change bead to affect peak to peak ripple?

     

    Change FB602 bead to 0Ω, 

    Thanks,

    Best Regards,

    Patty

     

     

  • 0 in reply to Patty Chuang
    TI__Genius 10070 points

    Hi,

    The bead can lead to the ringing, why does the customer want to add the bead? And can't they accept 88mV ripple?

    Shawn