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DS90UB954-Q1: Link broken by POC Noise

Anthony Yoo68
Expert 1320 points
Part Number: DS90UB954-Q1

HI


My customers are considering applying the DS90UB954-Q1.


However, when the test is performed at low temperature (-30 degree), the link is broken as shown in the waveform below.
Yellow: PASS
Blue: LOCK
Pink: POC 6.5V

Link drop time approx. 5ms

We do not see broken link when we test 6.5V power supply by connecting DC power supply after removing POC 6.5V power supply.
So we suspect the link broken due to POC power Noise. Noise of POC 6.5V power supply is 58mV pk-pk.

1. Is there a way to improve the problem by reducing the Noise by changing the Register for the above link breakage?


2. Is there any point to change POC block circuit and 954 peripheral circuit to improve noise?

3.What are the most important improvement points to improve this kind of thing (ex- circuit check and modification, PCB pattern check and modification, register change or etc...)

Below is a schematic.

PS) If necessary, PCB pattern information can also be shared.

Please check it.

Thank you

  • 0
    TI__Genius 11340 points

    Hi Anthony,

    On the schematics I only see one inductor for your PoC network. For 953-954 operation, we recommend using the following network for optimal performance:

    Additionally, we recommend increasing the PoC voltage to 9V. The recommended PoC network can only handle up to 250mA. If you increase the PoC voltage you can handle higher power consumption.

    Best,

    Jiashow