LM5164-Q1: Output Inductor selection

REDDY Y

Intellectual 860 points

Part Number: LM5164-Q1
Other Parts Discussed in Thread: LM5164

Dear Team,

We have a designed buck with LM5164.

With Vin range 30V-75Vdc (Typical 50V). Vout=0.3Amps Max. Whereas my Load current typical is 0.1A.

to get the max efficiency at light load i am planning to run PMIC at 125KHz.. which results into 330uH.

for the above spec (30Vin-70Vin, 5Vout,0.3Aout) In Webbench its recommonding 2Amps Inductor, and in Excel Calculator Its >1.8A.

as per the datasheet formulae calculation it IL(peak) = 0.3A+0.1A= 0.4A

Pls suggest .. Can i go with 0.6Amps Inductor (MPN EST1060T331MDGA, MAKE- TAIYO YUDEN) ??

over 3 years ago

0 REDDY Y over 3 years ago

Intellectual 860 points

0 REDDY Y over 3 years ago in reply to REDDY Y

Intellectual 860 points

0 Andy Chen over 3 years ago in reply to REDDY Y

TI__Mastermind 27045 points

Hi Reddy,

The Fsw set for normal load has no impact on light load efficiency. you may use much higher switching freq to reduce the inductor size.

The inductor saturation current should be >1.8A as the HS current may trip the max current limit during startup or load transient condition.

For cost down, you may use an inductor with saturation current round 0.6A~1A, then check its inductance at 1.8A which should be >50% of nominal value.

B R

Andy

0 REDDY Y over 3 years ago in reply to Andy Chen

Intellectual 860 points

will this be fine ??

0 Andy Chen over 3 years ago in reply to REDDY Y

TI__Mastermind 27045 points

Hi Reddy,

we should check the inductance at 1800mA.

Looks like the inductor shown on above Fig can't be used.

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LM5164-Q1: Output Inductor selection