Drum Core Power Inductors
Applications and Selections

What is a drum core?

A drum core consists of ferrite material and is named after its shape. Although resembling a drum, its physical size is a thousand times smaller than that of an actual musical drum. The drum core has two flat discs on its ends. The center post is narrower to keep the wires between the two ends. Due to the feature of the air gap flux path, a drum core can carry a higher current than a toroidal core without saturation. With this characteristic, a drum core is preferably designed for power inductors.

Applications End Products
  • Power supply
  • DC/DC converters
  • DC/AC inverters
  • Flash memory programmers
  • Field programmable gate array (FPGA)
  • Filters (low pass, high pass, band pass)
  • Audio circuits
  • Line matching circuits
  • Battery-powered devices
  • Computer equipment
    • Notebook computers
    • Hard disk drives
    • Video graphic cards
    • Printers
  • Telecom equipment
    • Modems
    • Mobile phones
    • Set-top-boxes
  • Consumer electronics
    • Game stations
    • Digital cameras
    • PDAs
    • LCD displays
    • CD players
    • VCRs
    • Televisions

 

How to SELECT a drum core inductor for the application?

Three main parameters need to be considered in selecting a drum core inductor:

  1. Inductance
  2. Rated current
  3. DC resistance

Inductance at rated current is the most critical parameter that is determined by the users for their application.

If a Drum Core Cannot Be Found,

If the inductance at rated current cannot be found in the drum core product range, the next alternative solution is to look for other inductor product families that are used a larger toroidal or E core with materials of iron powder, Kool-Mu, or MPP.

Selection Table

Package Styles P/N
Series
Range
(uH)
Rated Current Range
(A)
DCR
Range(Ω)
Package Size
L x W x H
(mm) (inches)
SMN
SMN
SMN1040 10 - 82 0.85 - 2.38 0.05 - 0.25 10.30X9.30X4.70 0.406X0.366X0.185
SMN1054 10 - 820 0.24 - 2.6 0.06 - 2.55 10.40X9.40X5.80 0.409X0.370X0.228
SMN4532 1 - 100 0.11 - 3.8 0.033 - 1.15 4.80X4.30X3.50 0.189X0.169X0.138
SMN5845 3.9 - 220 0.35 - 3.2 0.07 - 1.57 6.10X5.50X4.90 0.240X0.217X0.193
SMN7835 10 - 330 0.28 - 1.44 0.08 - 1.5 8.10X7.30X4.00 0.319X0.287X0.157
SMN7850 10 - 470 0.34 - 2.3 0.07 - 1.96 8.10X7.30X5.50 0.319X0.287X0.217
SMH
SMH
SMH1364 0.33 - 100 0.95 - 20 0.002 - 0.4 13.26X9.96X6.35 0.522X0.392X0.250
SMH2280 0.78 - 15 8 - 30 0.0026 - 0.032 22.35X16.26X8.00 0.880X0.640X0.315
SMH8950 0.56 - 47 0.87 - 7.7 0.01 - 0.47 9.19X6.40X5.00 0.362X0.252X0.197
 
SMQ
SMQ
SMQ1260 1.5 - 1000 0.4 - 16 0.003 - 1.53 12.50X12.50X8.00 0.492X0.492X0.315
SMQ1280 0.47 - 1000 0.55 - 35 0.002 - 1.82 12.50X12.50X8.00 0.492X0.492X0.315
SMQ6530 3.3 - 330 0.19 - 1.94 0.068 - 4.94 6.80X6.50X3.00 0.268X0.256X0.118
SMQ6550 10 - 1000 0.14 - 1.35 0.12 - 9.26 6.80X6.50X5.00 0.268X0.256X0.197
SMQ7535 1 - 1000 0.16 - 7.97 0.0093 - 9.44 7.80X7.80X3.50 0.307X0.307X0.138
SMQ7545 0.33 - 1000 0.18 - 8.5 0.017 - 6 7.80X7.80X4.50 0.307X0.307X0.177
SMS
SMS
SMS1137 5 - 82 0.4 - 1.7 0.08 - 0.98 11.00X8.20X3.70 0.433X0.323X0.146
SMS1145 2.2 - 120 0.45 - 2.5 0.04 - 1.12 11.00X8.20X4.50 0.433X0.323X0.177
SMS1351 1 - 390 0.3 - 5.6 0.021 - 4.51 13.25X10.10X5.10 0.522X0.398X0.201
SMS1976 1.2 - 1000 0.8 - 20 0.0045 - 2.01 18.54X15.24X7.62 0.730X0.600X0.300
SMS6630 1 - 10000 0.02 - 3 40 - 32800 6.90X4.50X2.92 0.271X0.177X0.115
 
SMU
SMU
SMU1311 6.8 - 1000 0.8 - 10 0.015 - 2 12.95X9.40X11.43 0.510X0.370X0.450
SMU1330 10 - 1000 0.1 - 2.4 0.11 - 8.4 12.95X9.40X11.43 0.510X0.370X450
SMU1352 1 - 1000 0.3 - 9 0.0092 - 3 12.95X9.40X5.21 0.510X0.370X0.205
SMU1971 2.2 - 1000 1 - 16 0.014 - 1.8 18.54X15.24X7.40 0.730X0.600X0.291
SMU6629 1 - 1000 0.1 - 2.9 0.05 - 13.8 6.60X4.50X2.92 0.260X0.177X0.115
 

 

 
Selected Table
Package Styles P/N Series Range
(uH)
Current
Range (A)
DCR
Range(O)
Size
(mm)
Size
(Inch)
SMN1040 10 - 82 0.85 - 2.38 0.05 - 0.25 10.30X9.30X4.70 0.406X0.366X0.185
SMN1054 10 - 820 0.24 - 2.6 0.06 - 2.55 10.40X9.40X5.80 0.409X0.370X0.228
SMN4532 1 - 100 0.11 - 3.8 0.033 - 1.15 4.80X4.30X3.50 0.189X0.169X0.138
SMN5845 3.9 - 220 0.35 - 3.2 0.07 - 1.57 6.10X5.50X4.90 0.240X0.217X0.193
SMN7835 10 - 330 0.28 - 1.44 0.08 - 1.5 8.10X7.30X4.00 0.319X0.287X0.157
SMN7850 10 - 470 0.34 - 2.3 0.07 - 1.96 8.10X7.30X5.50 0.319X0.287X0.217
SMH1364 0.33 - 100 0.95 - 20 0.002 - 0.4 13.26X9.96X6.35 0.522X0.392X0.250
SMH2280 0.78 - 15 8 - 30 0.0026 - 0.032 22.35X16.26X8.00 0.880X0.640X0.315
SMH8950 0.56 - 47 0.87 - 7.7 0.01 - 0.47 9.19X6.40X5.00 0.362X0.252X0.197
SMQ1260 1.5 - 1000 0.4 - 16 0.003 - 1.53 12.50X12.50X8.00 0.492X0.492X0.315
SMQ1280 0.47 - 1000 0.55 - 35 0.002 - 1.82 12.50X12.50X8.00 0.492X0.492X0.315
SMQ6530 3.3 - 330 0.19 - 1.94 0.068 - 4.94 6.80X6.50X3.00 0.268X0.256X0.118
SMQ6550 10 - 1000 0.14 - 1.35 0.12 - 9.26 6.80X6.50X5.00 0.268X0.256X0.197
SMQ7535 1 - 1000 0.16 - 7.97 0.0093 - 9.44 7.80X7.80X3.50 0.307X0.307X0.138
SMQ7545 0.33 - 1000 0.18 - 8.5 0.017 - 6 7.80X7.80X4.50 0.307X0.307X0.177
SMS1137 5 - 82 0.4 - 1.7 0.08 - 0.98 11.00X8.20X3.70 0.433X0.323X0.146
SMS1145 2.2 - 120 0.45 - 2.5 0.04 - 1.12 11.00X8.20X4.50 0.433X0.323X0.177
SMS1351 1 - 390 0.3 - 5.6 0.021 - 4.51 13.25X10.10X5.10 0.522X0.398X0.201
SMS1976 1.2 - 1000 0.8 - 20 0.0045 - 2.01 18.54X15.24X7.62 0.730X0.600X0.300
SMS6630 1 - 10000 0.02 - 3 40 - 32800 6.90X4.50X2.92 0.271X0.177X0.115
SMU1311 6.8 - 1000 0.8 - 10 0.015 - 2 12.95X9.40X11.43 0.510X0.370X0.450
SMU1330 10 - 1000 0.1 - 2.4 0.11 - 8.4 12.95X9.40X11.43 0.510X0.370X450
SMU1352 1 - 1000 0.3 - 9 0.0092 - 3 12.95X9.40X5.2 0.510X0.370X0.205
SMU1971 2.2 - 1000 1 - 16 0.014 - 1.8 18.54X15.24X7.40 0.730X0.600X0.291
SMU6629 1 - 1000 0.1 - 2.9 0.05 - 13.8 6.60X4.50X2.92 0.260X0.177X0.115

 

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