LM2733: EMI/EMC support for LM2733

Hi Tanvir,

Thank you for choosing TI boost converters.

There are several helpful tips to help improve EM/EMC: 1. Please follow the recommended layout in datasheet. This will make a big difference. 2. Reserve a RC snubber at SW pin to GND. If the original circuit can't pass CISPR22, place a proper RC snubber circuit. 3. Place a Ferrite bead at output.

Hi zack,

Hope you are well during this pandemic covid-19.

Thanks for valuable response.

I will add RC snubber across  SW to ground.

what will be the approx value of RC snubber and ferrite bead should i put?

addition to that i also add RC snubber across to output diode, high freq 100pf capacitor across input and output capacitor.

apart from this any suggestion because i am releasing final PCB now.

Major issue i am facing at radiated emission test noise level 70dbuv/m at 100MHz freq by other make IC.

awaiting for your feedback asap.

Hi Tanvir,

The suitable RC snubber value is related to the layout. Different layout has different PCB parasitics so you have to adjust it per below application note:

6131.Minimizing Ringing at the Switch Node of a Boost converter.pdf

Hi Zack,

Thanks for guide.

7563.SCHEMATIC1 _ PAGE1.pdfPlease check schematic once i have added all possible provisions to pass EMI.

Ferrite bead value i am putting general 4.7uH as per many application note.

awaiting for your reply.

Thanks,

Tanvir