LM5122-Q1: About LM5122-Q1 component

Tomohiro Nagasawa58

Expert 1570 points

Part Number: LM5122-Q1

Dear Support team

I have question about LM5122-Q1 component. Please give advice about below.

1)It there problem to attach the capacitor between GND and the SW pin for EMI?

2)Is there any problem to attach a pull-down resistor for LO pin?

Regards

Tomohiro Nagasawa

over 5 years ago

0 Jasper Li over 5 years ago

TI__Mastermind 46905 points

Hi Tomohiro -san

I found you build two posts about the questions of LM5122-Q1. could you help to put all the questions in one post? it is easy for us to focus and provide good supports.

0 Garrett Roecker over 5 years ago

TI__Mastermind 21720 points

Hi Tomohiro,

A capacitor should not be connected directly to the SW node. Typically and RC can be connected between SW and GND. This is called a snubber and helps to control the rise rate and ringing of the SW node. Take a look at this application note

www.ti.com/.../slva255.pdf

The pull down resistor between the GATE and SOURCE of the low side MOSFET can be populated. The value should be fairly high (~100kOhm). This just helps to ensure that the MOSFET is still turned on relatively quickly.

-Garrett

0 Tomohiro Nagasawa58 over 5 years ago in reply to Garrett Roecker

Expert 1570 points

Hello Garrett-san

Thank you for quick response.

I understand it.

Regards

Tomohiro Nagasawa

Power management

Power management forum

LM5122-Q1: About LM5122-Q1 component