LTC3777 audible hissing sound

DC2519A circuit was copied into prototype. There is a audible hissing sound. Could anyone advise what could have went wrong?

Vin=100V, Vout=24V@4A load test for 200mA.

  • 0
    •  Analog Employees 
    on Oct 29, 2020 8:22 AM 1 month ago

    Hi carmen,

    Audible noise is caused by high frequency vibration in the audible noise range, can mostly come from the magnetic components and in some cases from ceramic capacitors. It is not necessarily bad if end application is in closed or noisy environment. Manufacturability can be a cause too for loose parts. Thermal adhesive to bond component to board or coating on magnetics may help. Of course, more importantly you have to make sure the converter operation is stable and is not the cause of noise. Checking performance of DC2519A demo board is helpful.