LM5149-Q1: LM5149 deadtime spec

Scarlett Cao

Part Number: LM5149-Q1
Other Parts Discussed in Thread: LM5149

Hi team,

Could you please help share how the LM5149 20ns typ dead time is defined? Take LO off to HO on deadtime as example, is it counted from LO decreasing moment, or from LO dropping below the 2V threshold voltage?

Also customer would like to know if the deadtime is adjustable.

They need to understand this to consider the deadtime headroom with different gate resistor and gate cap.

Thank you

Scarlett

over 1 year ago

0 Orlando Murray over 1 year ago

TI__Mastermind 22299 points

Hi Scarlett,

The 20ns deadtime measurement is measured from command to command.

For example, it is when LO starts falling to when HO starts rising.

This will include the 7ns LO fall time in the datasheet.

The dead time will increase if the fall-time increases, with larger gate capacitances.

Hope this helps,

-Orlando

0 Cheng Hui over 1 year ago in reply to Orlando Murray

Prodigy 30 points

Thanks!

"The dead time will increase if the fall-time increases, with larger gate capacitances."

It seems there are some detection modules/methods to monitor the LO falling and HO rising behavior to prevent cross conduction? can you share the details?

Thanks!

0 Orlando Murray over 1 year ago in reply to Cheng Hui

TI__Mastermind 22299 points

Hi,

Correct, with adaptive deadtime, we wait for HO and LO to fall below 2V before turning on the other FET.

-Orlando

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LM5149-Q1: LM5149 deadtime spec