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LM73605-Q1: SCH review

Part Number: LM73605-Q1
Other Parts Discussed in Thread: LM73605

HI Team, 

My customer now use LM73605 in their 4D radar project.

Could you help to review the SCH?

Thanks!

  • Hi Amelie,

    Is the RT resistor not populated?

    If you are intended to run 500kHz then RT can be left floating. If you are running 2MHz switching frequency then the R322 need to be populated. 

    The other components looks ok. 

    Some things to check:

    1) I am not sure what is the output capacitor voltage rating. I would recommend 4x22uF, 16V output capacitor. 

    2) Inductor value of 4.7uH is ok for 2MHz design, for 500kHz design i would recommend 6.8uH - 10uH inductor with saturation current equal to the High Side Current limit of the part. 

    3) R321 value should be 0 ohm. This way the MODE/SYNC pin is a direct pullup to VCC for Forced PWM operation

    Thanks

    -Arief

  • Hi  Arief,

    The feedback is as following: 

    Is the RT resistor not populated?

    If you are intended to run 500kHz then RT can be left floating. If you are running 2MHz switching frequency then the R322 need to be populated. 

    G-PAL: populating R322 on board

     

    Some things to check:

    1)      I am not sure what is the output capacitor voltage rating. I would recommend 4x22uF, 16V output capacitor. 

    G-PAL: the total for output capacitor is 4x22uF, and the voltage is 16V

    2)      Inductor value of 4.7uH is ok for 2MHz design, for 500kHz design i would recommend 6.8uH - 10uH inductor with saturation current equal to the High Side Current limit of the part. 

    G-PAL: using 4.7uH inductor for 2MHz design

    3) R321 value should be 0 ohm. This way the MODE/SYNC pin is a direct pullup to VCC for Forced PWM operation

    G-PAL: modifying the value from 10K to 0R

  • Hi Amelie,

    Thank you for the update. After the modifications i think the design is good to go. 

    For the layout recommendation you can take a look at the datasheet page below

    Thanks

    -Arief