• State
  • Locked Locked
  • Replies 1 reply
  • Subscribers 62 subscribers
  • Views 539 views
  • Users 0 members are here
Support feedback
Options
Options
Related

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.

TLV62569: TLV62569 power supply to the radar as a sencond power supply results in an SPUR condition for the radar

Arabella Zhang
Expert 3610 points

Part Number: TLV62569

Tool/software:

Dears,

The customer used the TPS562201DDCR as the primary power supply and TLV62569DBVR as the secondary power supply to power the subsequent radar, and the customer found that the BUCK power supply caused the radar to have an SPUR condition.

1. The schematic diagram and PCB traces are shown in the attachment below, please help to check whether the schematic is correct?

3343.1-TI power schematic.pdf2705.TI power cables.pdf

Specifically, the inference for determining that BUCK causes the presence of SPUR on radar is as follows:
a. As attached to the original design, there is SPUR, as shown below.


b. Remove the primary power supply, and directly supply the power from the secondary 5V, with SPUR
c.The primary power supply is changed to TPS562208DDCR+4.7uH power inductor, the second stage is changed to LDO3.3V and then to LDO1.5V, and the 1.15V inductor is changed to 1uH.
Others remain unchanged, there is no SPUR (This scenario is only used to verify that the spur is caused by BUCK)

Please help analyze the cause, many thanks!

  • 0
    TI__Mastermind 21590 points

    Hi Arabella,

    The schematic looks fine. It will be useful if they can send the layout of IC itself. I wasn't able to find the footprints of the IC and the input/output caps from the layout PCB shared.

    The customer can try the following things:

    • Add an extra LC filtering using ferrite beads on the input and output rails to localize the noise and the prevent the noise from propagating to other parts of the board.
    • Make sure all the GND pads of the input and output caps have via placed close to them. There should be vias close to the IC GND pin as well. 2nd layer of PCB should be GND plane.

    Best regards,

    Varun