Inductor Selection for Buck-Boost Regulator


flux

For a 5 A-capable buck-boost inductor, these are solid options from the library based on datasheet values:
Inductor options

Table


PartInductanceIrms / Rated CurrentIsatDCRPackageNotes
FXL0420-1R0-M1.0 µH5.4 A max, 6 A typ5.6 A max, 7 A typ27 mΩ max4.4 x 4.2 x 1.8 mmSmallest option, but not much margin above 5 A
APS0630M1R0A1.0 µHfamily includes much higher-current partsfamily includes much higher-current partspackage family includes low-DCR options6.6 x 7.7 x 3.0 mm classPromising family, but exact row for this specific variant should be double-checked before finalizing
SLW8040S1R0MST1.0 µH ±20%6.30 A9.85 A8 mΩ typ8.0 x 8.0 x 4.2 mmBest margin here; safest pick of these three
My recommendation
If you want the safest choice from these results, use SLW8040S1R0MST.
Why:
  • Irms = 6.3 A gives real thermal margin over your 5 A requirement
  • Isat = 9.85 A gives better peak current headroom
  • DCR = 8 mΩ is much better than the smaller option, so it will run cooler
Important note
A 5 A current rating alone is not enough to finalize the inductor. The correct inductance value depends on:
  • input voltage range
  • output voltage
  • switching frequency
  • allowed ripple current
If you give me:
  • Vin min / max
  • Vout
  • switching frequency
  • whether the 5 A is output current or inductor peak/current target
I can narrow this to the right inductance value and pick the best exact part.
I need i nthe range of 15 to 30uH. I am already with a margin at 5A. So max is 6.3A

flux

A good match is CSBX1670-220M.
Recommended inductor

Table


PartInductanceCurrentDCRTypeWhy it fits
CSBX1670-220M22 µH8.5 A23.5 mΩ maxShielded wirewound SMDLands in your 15 to 30 µH target and stays comfortably above your 6.3 A limit
This is the cleanest fit I found for your updated requirement:
  • inductance in range: 22 µH
  • current capability above your ceiling: 8.5 A
  • shielded power inductor
  • reasonable DCR for this value/current class
If you want, I can next narrow it further by:
  • smallest footprint
  • lowest DCR
  • best availability/cost
Or I can help choose whether 15 µH, 22 µH, or 30 µH is best for your exact buck-boost operating point.
Compare 15/22/30uH
Lowest DCR option
Smallest footprint
Best cost availability

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36 Ω
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10kΩ
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22 Ω
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10kΩ
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10kΩ
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22 Ω
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36 Ω
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10kΩ
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36 Ω
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10kΩ
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10kΩ
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10kΩ
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330 Ω
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330 Ω
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1kΩ
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Capacitance
1uF
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Capacitance
10uF
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1uF
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0.1uF
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10uF
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1uF
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1uF
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1uF
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10uF
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Capacitance
100nF
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Capacitance
0.1uF
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Capacitance
0.1uF
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