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CSD97376Q4M: CSD97376Q4M No Output

Max Gui
Prodigy 100 points
Part Number: CSD97376Q4M

Hello, I am using CSD97376Q4M but do not see any output. The following figure is the PWM signal send every 500ms. I can confirm that SKIP#, VDD, and Vin are connected to 5V. 

The following figure is measured at the BOOT pin. I do take this chip on and off multiple times, should I suspect that it is dead? Thank you very much! 

  • 0
    TI__Expert 3525 points

    Hi Max,

    I have few questions for me to better understand the issue. If you haven't tried some below items, maybe you can check so we can narrow down the possible root causes.

    Do you have the schematic for the circuit you tested the device? 

    For the BOOT voltage you measured, are you seeing 4.78V DC voltage? I am not very sure if I understand the waveform correctly.

    If you measure on VSW, do you just see 0V or any waveform can be saved?

    How does the PWM waveform looks like (duty, frequency, etc) if you zoom in?

    Have you tried to replace with a brand new device to see if circuit works?

    Best,

    Qingquan

  • 0 in reply to Qingquan Tang
    Prodigy 100 points

    Hi Qingquan

    I don't see any DC voltage at the BOOT pin. I guess the waveform I am showing just noise. I will try to place this IC and see if it works. This is my circuit schematic: 

  • 0 in reply to Max Gui
    TI__Expert 3525 points

    Hi Max,

    Did you measure voltage directly on Vin pin? I noticed your Vin is connected to 5V through 20ohm resistor, which is very high impedance. Please make sure the voltage on VIN pin.

    For each device, please add 2.2uf bypass caps as close as possible to VDD pin, and add 1uf/0402 decoupling cap between VIN/PGND as close as possible to power stage.

    Best,

    Qingquan

  • 0 in reply to Qingquan Tang
    Prodigy 100 points

    Problem solved... The ICs dead. Replace with a new one and it works.