Unstable switching frequency LTC3633

Hello,

You can adjust the values of ITH1 and ITH2 resistors and/or capacitors to make it stable. It will be helpful if you can see the bode plot of your system. If not, you can adjust the values of ITH components until it is stable.

Regards,

Jhun

Hi Jhun,

Thanks for your advice! 

But I have noticed a more severe unstable frequency. I have designed a board with a schematic and layout almost identical to the DC1347B. The PMIC works fine initially after power up. But after around 2 minutes, its switching frequency suddenly increase to 8Mhz and become unstable, as shown in the video:

I am wondering whether you can give any suggestion on this?

Best,

Piao

Hi Jhun,

Thanks for your advice! 

But I have noticed a more severe unstable frequency. I have designed a board with a schematic and layout almost identical to the DC1347B. The PMIC works fine initially after power up. But after around 2 minutes, its switching frequency suddenly increase to 8Mhz and become unstable, as shown in the video:

I am wondering whether you can give any suggestion on this?

Best,

Piao