TPS5410-EP: Cannot calculate inductor rms current and peak current

Michael Falzone

Part Number: TPS5410-EP

Tool/software:

Is there an issue with equations 5 and 6 in the datasheet for this IC? I cant seem to get values that make sense (peak current less than my desired output current). Am I doing this wrong? Or is there possibly another way to verify those two values before selecting an inductor? My values are seen below:

Thank you

Vout [V]	5
Vin(max) [V]	30.5
K_IND	0.3
I_OUT [A]	0.5
F_SW [Hz]	500000
L_MIN [H]	6.96721E-05

4 months ago

0 Rahil Ajani 4 months ago

TI__Expert 6960 points

Hi,

The peak current should be higher, maybe there was a calculation mistake?

For 30Vin to 5Vout, the recommended inductor value is 68uH.

The saturation current should be a little higher than max current of device, 2A saturation should be sufficient.

Regards,

Rahil

0 Michael Falzone 4 months ago in reply to Rahil Ajani

Prodigy 20 points

Is this true even if im sizing the buck to output 500mA max for my needs? I dont need 1A of capacity. Those numbers I gave are what I used for calculating equations 4,5 and 6. I figured I could use a 68mH inductor, but sized for about 600mA, and saturation point could in turn be much lower than needed for 1A of capacity. Is this possible?

+1 Rahil Ajani 4 months ago in reply to Michael Falzone

TI__Expert 6960 points

Hi,

Yes, we recommend sizing it based on the max Iout of the device not the application.

Regards,

Rahil

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TPS5410-EP: Cannot calculate inductor rms current and peak current