AppNote uMetals Comparison and Examples Iron Powder Cores

862019 AppNote uMetals Comparison and Examples Iron Powder Cores

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APPLICATION NOTES

MICROMETALS INC bull 5615 E LA PALMA AVENUE bull ANAHEIM CALIFORNIA 92 807-2109 bull USA

1

An Objective Comparison of Powder Core Materials for Inductive Componentswith Selected Design Examples

Dale J Nicol

Micrometals Inc

Abstract

Engineers and magnetics designers need to understand the differences betweeniron powder and sendust powder core materials This paper explains the basicperformance differences between the two types of powder materials includingapplications design examples with cost goals basic design guidelines andthermal aging

Discussion

Engineers today are under severe pressure to use the lowest cost core materialsand sometimes have not fully understood the subtle differences between ironpowder and sendust As a result iron powder core materials have gotten a badrap in recent times due to misapplication or insufficient testing of the prototypethat would have uncovered potential thermal lifetime problems with the design

The purpose of this article is to point out the differences between these

commonly used distributed air gap core materials the importance of using sounddesign guidelines and available software design tools

Iron powder is the least expensive magnetic material available and its propertiesmake it well suited for most inductor applications Its relatively low permeabilityand high saturation flux density give it high energy storage capabilities with a softsaturation curve While its core loss properties do not make it a good choice for discontinuous mode flybacks and switching transformers they are generallyacceptable for most inductors Typical applications include



2


bull 60 Hz Differential-Mode EMI Chokesbull

DC Output Chokesbull Power Factor Chokes (PFC)bull Resonant Inductorsbull Hall Effect Sensor Coresbull Boost or Buck Inductorsbull Flux-Path or Shunt Cores Placed in Ferrite Gaps to reduce Fringing Fluxbull Light Dimmer Chokes

Material Comparison

Figure 1 shows the similarities in DC Saturation characteristics betweenMicrometals Mix ndash52 and the 75micro sendust materials Both core materials are 75micromaterials

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110

1 10 100 1000

Hdc - DC M agnetizing F orce (Oe)

I n i t i a l P e r m e a b i l i t y

Sendust 75micro

-52 Material

Figure 1 Initial Permeability vs Hdc

Figure 2 shows the similarities in DC saturation characteristics betweenMicrometals Mix ndash18 (micro = 55) and the 60micro sendust You can see the saturationcharacteristics are about the same to 100 Oe and then the iron powder holds upa little better at higher drive levels



3


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110

1 10 100 1000

Hdc - DC M agnetizing Force (Oe)


Sendust 60micro

-18 Material


Since the sendust cores are not available in permeabilityrsquos below 26 Figure 3shows the next best comparison using Micrometals Mix ndash2 with a perm of 10For applications with very high surge currents Figure 3 shows that MicrometalsMix ndash2 is very difficult to saturate and still maintains 100 of its initial inductance

at 100 Oe

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1 10 100 1000


I n i t

i a l P e r m e a b i l i t y

Sendust 26micro

-2 Material



4


Figure 3 Initial Permeability vs HdcOne major difference between iron powder and sendust materials is how theinitial permeability reacts to increasing Peak AC Flux Density levels

Figure 4 shows how Micrometals 10micro 55micro and 75micro materials will change withincreasing Peak AC Flux Density The smallest change is observed with the 10micromaterial In comparison the 26micro sendust material will change about +1 at 500gauss and the 75micro sendust material will change about +20 at 500 gauss

Figure 4 Initial Permeability vs Bpk

Figures 5 and 6 shows the core loss at 25 kHz and 100 kHz In all cases the coreloss of sendust is lower than the iron powder materials

As the frequency of operation increases to 500 kHz Figure 7 shows the

Micrometals Mix ndash2 core loss to be less than or the same as the sendust

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10 100 1000 10 000

Bpk - Peak AC Flux Density (G)


-18 Material

-2 Material

-52 Material



5


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C o r e L o s s ( m W c m sup3 )

-18 Material

-2 Material

-52 Material

Sendust

Figure 5 Core Loss vs Bpk ndash 25 kHz

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10 100 1000 10000



-18 Material

-2 Material

-52 Material

Sendust




6



Figures 8 9 and 10 show the differences in initial permeability vs frequencyThese differences are important to be aware of depending on the intendedapplication As an example for differential mode inductors select a core materialwhose permeability decreases with increasing frequency like the Micrometals Mix

ndash52 or ndash26 For a broadband inductor application select a core material whosepermeability changes much less with increasing frequency like the lower permeability materials

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10 100 1000 10 000



-18 Material

-2 Material

-52 Material

Sendust



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Frequency (Hz)


Sendust 75micro

-52 Material

Figure 8 Initial Permeability vs Frequency

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Frequency (Hz)


Sendust 60micro

-18 Material




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Frequency (Hz)


Sendust 26micro

-2 Material


Figures 11 and 12 show the change in permeability over temperature for thesendust and iron powder materials You will notice iron powder in all cases has a

positive Tc over temperature

Figure 11 Change in Permeability vs Temperature ndash Sendust



9


Figure 12 Change in Permeability vs Temperature ndash Iron Powder

Design Examples

The following design examples will illustrate differences in the powder corematerial losses and when they are important or not important

60 HZ Differential Mode Design Example Comparison

A comparison of these materials in a 60 Hz differential mode choke requiring aminimum of 50 microH at 12 amperes follows

Design Requirementsbull Minimum Inductance 50 microHbull DC Current 12 A

bull Frequency 60 Hz + HF Noisebull Maximum Size 125rdquo ODbull Maximum Temp Rise 55 Cdegbull Target Core Cost $020

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Tem perature (degC)

C h a n g e i n P e r m e a b i l i t y

-18 Material

-2 Material

-52 Material



10


Table 1 Differential Mode Design Example

Iron Powder SendustPart Number T106-52 77935-A7AL (nHNsup2) 95 94Turns 35 35AWG 16 16Bpk 60 Hz (G) 2571 2571Core Loss (mWcmsup3) 91000 01086Core Volume (cmsup3) 428 415Core Loss (mW) 39000 0451Copper Loss (mW) 3230 3230Total Loss (mW) 3269 3230Wound Surface Area (cmsup2) 31 31

Maximum Size (in) 12 12∆∆∆∆T (Cdeg) 49 48Approx Core Cost (per piece) $014 $090OD (in) 106 106ID (in) 057 058Ht (in) 0437 044

This shows that while the core loss characteristics of the sendust are significantlylower than the iron powder that in this application it is not one of the controlling

factors and only saves 1Cdeg in temperature rise However the difference in cost isvery significant with the iron powder core at $014 compared to $090 for thesendust

In this type of application where it is necessary to suppress high frequency noisethe winding details can have a profound impact on the performance Figure 13shows impedance vs frequency results for the iron powder coil with a 720deg (twicearound) winding and a progressivebackwound winding (once around)



11


D I F F E R E N T IA L M O D E I N D U C T O R S I M P E D A N C E T E S T R E S U L T S O F T W O W I N D I N G

C O N F I G U R A T I O N S

M I C R O M E T A L S P N T 1 0 6- 52 W O U N D W IT H 3 5 T U R N S O F A W G - 1 6

S R F 355 M H z 60 M H z

Z 1M H z 700 ohm s 709 ohm s

Z 10M H z 828 ohm s 299K ohm s




Figure 13 Differential Mode Inductor Winding Types

The progressivebackwound part produces significantly greater impedance at thehigher frequencies by minimizing the capacitive effects in the winding

Buck Inductor Design Comparison

The second comparison is for a buck inductor with the following designrequirements


bull Frequency 100 kHzbull Epk Input 5Vbull EDC Output 3V

The two designs compare as follows



12


Table 2 Buck Inductor Design Example

Iron Powder SendustPart Number T68-52A 77225-A7AL (nHNsup2) 54 43Turns 12 13AWG 14 14Bpk 100 kHz (G) 323 375Core Loss (mWcmsup3) 343 117Core Volume (cmsup3) 1030 0789Core Loss (mW) 354 92Copper Loss (mW) 1347 937Total Loss (mW) 1701 1029Wound Surface Area (cmsup2) 133 120

Maximum Size (in) 0825 x 0425 0825 x 0425∆∆∆∆T (Cdeg) 57 41Approx Core Cost (per piece) $007 $041OD (in) 069 065ID (in) 037 04Ht (in) 025 025

This shows the iron powder coil is larger with a total loss of 170 watts and atemperature rise of 57Cdeg compared to a total loss of 103 watts and atemperature rise of 41Cdeg for the sendust With the iron powder core at $007 and

the sendust at $041 the sendust should only be used when size and efficiencytake priority over cost

Thermal Aging

If this design must operate in a 55degC ambient the iron powder core will run at112degC Since iron powder cores undergo thermal aging it is essential to consider the long-term effects of operating under these conditions Micrometals hasdeveloped the ability to provide such a thermal aging profile as shown



13


Figure 14 Core Operating Temperature vs Time

This shows the core will operate reliably for well beyond 1 million hours (114years)

It required a great deal of time and effort for Micrometals to gather the data anddevelop the models required to make these predictions and the results are onlyvalid for cores manufactured by Micrometals Micrometals has encountered

numerous situations where a Micrometals core will operate reliably in a designand a competitorrsquos core will not A specific case in point is illustrated in Figure15

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1000 10000 100000 1000000 10000000 100000000

Time (hours)

C o r e O p e r a t i n g T e m p ( deg C )

T68-52A 100 kHz 323 G 55degC Ambient



14



This shows that the competitorrsquos core has somewhat higher core loss causing itto operate at a maximum temperature of 139degC where the Micrometals corestarts at 132degC We characterized the competitorrsquos thermal profile and found thatit was dramatically worse than for the standard Micrometals core This results inthermal runaway of the competitorrsquos core after less than 30000 hours where theMicrometals core will operate for over 300000 hours Even if the ambient

temperature is raised on the Micrometals core to create an initial startingtemperature equal to the competitorrsquos core the Micrometals core will last almost7 times longer

This illustrates that while the competitorrsquos core will pass incoming inspection andinitial burn-in of the power supply it will fail after less than 2 years in the fieldThis is just what is happening and has created an enormously expensive recallproblem

60 Hz Dimmer example

Design Requirementsbull Minimum Inductance 16 mHbull RMS Current 12 Abull Frequency 60 Hzbull Maximum Size 275rdquo ODbull Maximum Temp Rise 85degCbull Target Core Cost $065

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1000 10000 100000 1000000

Time (hours)


T90-26 75 kHz 633 G

Competitor - 55degC Ambient

MM - 55degC Ambient

MM - 61degC Ambient



15


The 60Hz inductor design is very similar to the Differential mode inductor sincethe both are driven to higher peak AC flux levels at 60 Hz In addition the ironpowder core material will do a better job suppressing the high frequency noisedue to its loss characteristics

Table 3 60 Hz Dimmer DesignIron Powder sendust-type

Part Number T225-26 77214-A7AL (nHNsup2) 98 94Turns 143 130AWG 14 14Bpk 60 Hz (kG) 112 143

Core Loss (mWcmsup3) 13900 334Core Volume (cmsup3) 2070 2065Core Loss (mW) 2770 69Copper Loss (mW) 12250 11220Wound Surface Area (cmsup2) 110 110Maximum Size (in) 255 255∆∆∆∆T (Cdeg) 61 49Approx Core Cost (per piece) $056 $380OD (in) 225 225ID (in) 1405 14Ht (in) 055 055

In reviewing the two designs the 12 Cdeg difference has no impact on theoperational lifetime and the clear choice is to select the iron powder coreThe design engineer has just saved approximately $324 in core cost byselecting the T225-26 iron powder core

PFC Chokes

Another popular application for iron powder cores is PFC boost chokes This can

be a very demanding application where core loss calculation is more complexand often misunderstood This can lead to poor designs that will have reliabilityproblems Micrometals has an application note which addresses proper coreloss analysis for PFC boost chokes as well as design software that covers thisapplication



16


Consider the following design example

Design Requirementsbull Minimum Inductance 250 microHbull Peak Current 7 Abull Frequency 100 kHzbull Epk Input 120Vbull EDC Output 400V

Table 4 PFC Choke Design Comparisons1 2 3

Part Number E168-52 E168-52 E168-2

AL (nHNsup2) 179 179 44Turns 45 90 76AWG 14 17 16Bpk 100 kHz (G) 389 195 230Core Loss (mWcmsup3) 4890 1200 615Core Volume (cmsup3) 185 185 185Core Loss (mW) 9063 2220 1137Copper Loss (mW) 866 3480 2324Total Loss (mW) 9929 5700 3461Wound Surface Area (cmsup2) 667 667 667Maximum Size (in) 17 x 17 17 x 17 17 x 17∆∆∆∆T (Cdeg) 65 41 27Approx Core Cost (per piece) $023 $023 $055Thermal Life (Hours) lt12000 ~1000000 gt10000000



17


Figure 16 Core Operating Temperature vs Time ndash PFC Designs

Example 1 is a design that is dominated by 906 watts of core loss with only087 watts of copper loss This results in a temperature rise of 65Cdeg With anambient of 55degC this part will have thermal runaway in less than 2 years

Example 2 shows that with the same core by simply increasing the number of turns with the required smaller wire size the core and copper losses will becomemore balanced This results in improved efficiency (saves 43 watts) a lower operating temperature (∆T=24Cdeg) and a dramatic improvement in thermal life(almost 2 orders of magnitude) While it may seem obvious that example1 is apoor design this is a fairly common mistake

If the higher inductance produced by adding turns in example 2 is unacceptablein the circuit the core and copper losses can also be better balance by selecting

a lower permeability material Example 3 illustrates how the Micrometals 10micro -2material performs This choke will be the most efficient and reliable but thisgrade of material is somewhat more expensive than the ndash52 Material

While Micrometals can provide the tools to make the illustrated thermal lifepredictions this information will only be valid upon experimental verification of the actual worst case operating temperature Where a fan is being used to helpreduce temperatures measurements need to be taken at various locations to find

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100 1000 10000 100000 1000000 10000000

Time (hours)

C o r e O p e r a t i n g T e m p ( deg

C )

PFC 1

PFC 2

PFC 3



18


the worst-case hot spot This can accomplished by drilling a small hole in thecore to accept a thermocouple The actual operating temperature may besomewhat higher or lower than predicted depending on the exact environment Itis recommended that an adjustment equal to this difference be made in theambient temperature and then re-run the thermal life prediction

It is also important to be extremely careful with the use of variable speed fansOften these fans will move less air at lower power levels Unfortunately in mostdesigns the core loss does not decrease at lower power levels so in a core lossdominated design it is possible to have a choke actually run hotter at low power than it will at high power

Basic Design Rules

The maximum ambient temperature will set the upper temperature rise limitationof the design based on the previous thermal aging discussion

Start the design with 5050 division of core loss to copper loss Complete thedesign so the copper loss is dominant because it is always easier to remove heatfrom the winding than the heat in the core material

Use the Micrometals design software Thermal Aging feature to help guide your selection of design solutions that will meet the operational lifetime parametersConsult the Micrometals office in Anaheim California if you have any questionsabout your design or application When using the design software make surethe ambient temperature default has been adjusted for your application Thedefault is preset to 25 C deg

If forced air flow is available make sure the fan is not a variable speed type thatchanges speed and airflow based on output power delivered by the power supply This becomes a critical issue if the core loss is high and the fan is relied

upon to reduce the temperature Many inductor applications today have constantcore loss regardless of the load current

Validate the design by making careful thermal measurements of the internal coretemperature and coil temperature Last but not least do not be afraid to askquestions if you do not fully understand magnetics design Micrometals offersfree applications help



19

Conclusion

Iron powder is a very cost-effective solution for a wide variety of inductors inpower conversion and EMI filtering applications It has been shown that their proper application is essential to insure long term reliability

Micrometals has developed an updated version of the design software thatincludes thermal aging predictions that are only valid for Micrometals cores Asmore an more competitors attempt to confuse the user by copying Micrometalscolor codes it is more important than ever to properly control your supply chainto insure that only cores with proven reliability are used



2


bull 60 Hz Differential-Mode EMI Chokesbull

DC Output Chokesbull Power Factor Chokes (PFC)bull Resonant Inductorsbull Hall Effect Sensor Coresbull Boost or Buck Inductorsbull Flux-Path or Shunt Cores Placed in Ferrite Gaps to reduce Fringing Fluxbull Light Dimmer Chokes

Material Comparison

Figure 1 shows the similarities in DC Saturation characteristics betweenMicrometals Mix ndash52 and the 75micro sendust materials Both core materials are 75micromaterials

0

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30

40

50

60

70

80

90

100

110

1 10 100 1000

Hdc - DC M agnetizing F orce (Oe)


Sendust 75micro

-52 Material


Figure 2 shows the similarities in DC saturation characteristics betweenMicrometals Mix ndash18 (micro = 55) and the 60micro sendust You can see the saturationcharacteristics are about the same to 100 Oe and then the iron powder holds upa little better at higher drive levels



3


0

10

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1 10 100 1000



Sendust 60micro

-18 Material



at 100 Oe

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1 10 100 1000


I n i t


Sendust 26micro

-2 Material



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-52 Material



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-52 Material

Sendust


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10 100 1000 10000



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-52 Material

Sendust




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-52 Material

Sendust



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Sendust 75micro

-52 Material


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Frequency (Hz)


Sendust 60micro

-18 Material




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Frequency (Hz)


Sendust 26micro

-2 Material







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Design Examples






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Tem perature (degC)


-18 Material

-2 Material

-52 Material



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S R F 355 M H z 60 M H z















12







Thermal Aging




13






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1000 10000 100000 1000000 10000000 100000000

Time (hours)





14








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1000 10000 100000 1000000

Time (hours)


T90-26 75 kHz 633 G


MM - 55degC Ambient

MM - 61degC Ambient



15







PFC Chokes





16





Part Number E168-52 E168-52 E168-2




17








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80

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120

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100 1000 10000 100000 1000000 10000000

Time (hours)


C )

PFC 1

PFC 2

PFC 3



18




Basic Design Rules









19

Conclusion





3


0

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100

110

1 10 100 1000



Sendust 60micro

-18 Material



at 100 Oe

0

10

20

30

40

50

60

70

80

90

100

110

1 10 100 1000


I n i t


Sendust 26micro

-2 Material



4








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240

260

280

10 100 1000 10 000



-18 Material

-2 Material

-52 Material



5


10

10 0

1000

10000

10 100 1000 10000



-18 Material

-2 Material

-52 Material

Sendust


10

10 0

1000

10000

10 100 1000 10000



-18 Material

-2 Material

-52 Material

Sendust




6





10

10 0

1000

10000

10 100 1000 10 000



-18 Material

-2 Material

-52 Material

Sendust



7


40

45

50

55

60

65

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80

1000 10 000 100000 1000000 10 000 000

Frequency (Hz)


Sendust 75micro

-52 Material


52

53

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55

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60

61

1000 10 000 100000 1000000 10 000 000

Frequency (Hz)


Sendust 60micro

-18 Material




8


0

5

10

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25

30

1000 10 000 100000 1000000 10 000 000

Frequency (Hz)


Sendust 26micro

-2 Material







9



Design Examples






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6

8

-65 -45 -25 -5 15 35 55 75 95 115

Tem perature (degC)


-18 Material

-2 Material

-52 Material



10










11





S R F 355 M H z 60 M H z















12







Thermal Aging




13






60

80

100

120

140

160

180

200

1000 10000 100000 1000000 10000000 100000000

Time (hours)





14








60

80

100

120

140

160

180

200

220

240

1000 10000 100000 1000000

Time (hours)


T90-26 75 kHz 633 G


MM - 55degC Ambient

MM - 61degC Ambient



15







PFC Chokes





16





Part Number E168-52 E168-52 E168-2




17








60

80

100

120

140

160

180

200

220

100 1000 10000 100000 1000000 10000000

Time (hours)


C )

PFC 1

PFC 2

PFC 3



18




Basic Design Rules









19

Conclusion





4








100

120

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220

240

260

280

10 100 1000 10 000



-18 Material

-2 Material

-52 Material



5


10

10 0

1000

10000

10 100 1000 10000



-18 Material

-2 Material

-52 Material

Sendust


10

10 0

1000

10000

10 100 1000 10000



-18 Material

-2 Material

-52 Material

Sendust




6





10

10 0

1000

10000

10 100 1000 10 000



-18 Material

-2 Material

-52 Material

Sendust



7


40

45

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1000 10 000 100000 1000000 10 000 000

Frequency (Hz)


Sendust 75micro

-52 Material


52

53

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55

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60

61

1000 10 000 100000 1000000 10 000 000

Frequency (Hz)


Sendust 60micro

-18 Material




8


0

5

10

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25

30

1000 10 000 100000 1000000 10 000 000

Frequency (Hz)


Sendust 26micro

-2 Material







9



Design Examples






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2

4

6

8

-65 -45 -25 -5 15 35 55 75 95 115

Tem perature (degC)


-18 Material

-2 Material

-52 Material



10










11





S R F 355 M H z 60 M H z















12







Thermal Aging




13






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180

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1000 10000 100000 1000000 10000000 100000000

Time (hours)





14








60

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120

140

160

180

200

220

240

1000 10000 100000 1000000

Time (hours)


T90-26 75 kHz 633 G


MM - 55degC Ambient

MM - 61degC Ambient



15







PFC Chokes





16





Part Number E168-52 E168-52 E168-2




17








60

80

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120

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220

100 1000 10000 100000 1000000 10000000

Time (hours)


C )

PFC 1

PFC 2

PFC 3



18




Basic Design Rules









19

Conclusion





5


10

10 0

1000

10000

10 100 1000 10000



-18 Material

-2 Material

-52 Material

Sendust


10

10 0

1000

10000

10 100 1000 10000



-18 Material

-2 Material

-52 Material

Sendust




6





10

10 0

1000

10000

10 100 1000 10 000



-18 Material

-2 Material

-52 Material

Sendust



7


40

45

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80

1000 10 000 100000 1000000 10 000 000

Frequency (Hz)


Sendust 75micro

-52 Material


52

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Frequency (Hz)


Sendust 60micro

-18 Material




8


0

5

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Frequency (Hz)


Sendust 26micro

-2 Material







9



Design Examples






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2

4

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8

-65 -45 -25 -5 15 35 55 75 95 115

Tem perature (degC)


-18 Material

-2 Material

-52 Material



10










11





S R F 355 M H z 60 M H z















12







Thermal Aging




13






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1000 10000 100000 1000000 10000000 100000000

Time (hours)





14








60

80

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140

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220

240

1000 10000 100000 1000000

Time (hours)


T90-26 75 kHz 633 G


MM - 55degC Ambient

MM - 61degC Ambient



15







PFC Chokes





16





Part Number E168-52 E168-52 E168-2




17








60

80

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120

140

160

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220

100 1000 10000 100000 1000000 10000000

Time (hours)


C )

PFC 1

PFC 2

PFC 3



18




Basic Design Rules









19

Conclusion





6





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1000

10000

10 100 1000 10 000



-18 Material

-2 Material

-52 Material

Sendust



7


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Frequency (Hz)


Sendust 75micro

-52 Material


52

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Frequency (Hz)


Sendust 60micro

-18 Material




8


0

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Frequency (Hz)


Sendust 26micro

-2 Material







9



Design Examples






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6

8

-65 -45 -25 -5 15 35 55 75 95 115

Tem perature (degC)


-18 Material

-2 Material

-52 Material



10










11





S R F 355 M H z 60 M H z















12







Thermal Aging




13






60

80

100

120

140

160

180

200

1000 10000 100000 1000000 10000000 100000000

Time (hours)





14








60

80

100

120

140

160

180

200

220

240

1000 10000 100000 1000000

Time (hours)


T90-26 75 kHz 633 G


MM - 55degC Ambient

MM - 61degC Ambient



15







PFC Chokes





16





Part Number E168-52 E168-52 E168-2




17








60

80

100

120

140

160

180

200

220

100 1000 10000 100000 1000000 10000000

Time (hours)


C )

PFC 1

PFC 2

PFC 3



18




Basic Design Rules









19

Conclusion





7


40

45

50

55

60

65

70

75

80

1000 10 000 100000 1000000 10 000 000

Frequency (Hz)


Sendust 75micro

-52 Material


52

53

54

55

56

57

58

59

60

61

1000 10 000 100000 1000000 10 000 000

Frequency (Hz)


Sendust 60micro

-18 Material




8


0

5

10

15

20

25

30

1000 10 000 100000 1000000 10 000 000

Frequency (Hz)


Sendust 26micro

-2 Material







9



Design Examples






-8

-6

-4

-2

0

2

4

6

8

-65 -45 -25 -5 15 35 55 75 95 115

Tem perature (degC)


-18 Material

-2 Material

-52 Material



10










11





S R F 355 M H z 60 M H z















12







Thermal Aging




13






60

80

100

120

140

160

180

200

1000 10000 100000 1000000 10000000 100000000

Time (hours)





14








60

80

100

120

140

160

180

200

220

240

1000 10000 100000 1000000

Time (hours)


T90-26 75 kHz 633 G


MM - 55degC Ambient

MM - 61degC Ambient



15







PFC Chokes





16





Part Number E168-52 E168-52 E168-2




17








60

80

100

120

140

160

180

200

220

100 1000 10000 100000 1000000 10000000

Time (hours)


C )

PFC 1

PFC 2

PFC 3



18




Basic Design Rules









19

Conclusion





8


0

5

10

15

20

25

30

1000 10 000 100000 1000000 10 000 000

Frequency (Hz)


Sendust 26micro

-2 Material







9



Design Examples






-8

-6

-4

-2

0

2

4

6

8

-65 -45 -25 -5 15 35 55 75 95 115

Tem perature (degC)


-18 Material

-2 Material

-52 Material



10










11





S R F 355 M H z 60 M H z















12







Thermal Aging




13






60

80

100

120

140

160

180

200

1000 10000 100000 1000000 10000000 100000000

Time (hours)





14








60

80

100

120

140

160

180

200

220

240

1000 10000 100000 1000000

Time (hours)


T90-26 75 kHz 633 G


MM - 55degC Ambient

MM - 61degC Ambient



15







PFC Chokes





16





Part Number E168-52 E168-52 E168-2




17








60

80

100

120

140

160

180

200

220

100 1000 10000 100000 1000000 10000000

Time (hours)


C )

PFC 1

PFC 2

PFC 3



18




Basic Design Rules









19

Conclusion





9



Design Examples






-8

-6

-4

-2

0

2

4

6

8

-65 -45 -25 -5 15 35 55 75 95 115

Tem perature (degC)


-18 Material

-2 Material

-52 Material



10










11





S R F 355 M H z 60 M H z















12







Thermal Aging




13






60

80

100

120

140

160

180

200

1000 10000 100000 1000000 10000000 100000000

Time (hours)





14








60

80

100

120

140

160

180

200

220

240

1000 10000 100000 1000000

Time (hours)


T90-26 75 kHz 633 G


MM - 55degC Ambient

MM - 61degC Ambient



15







PFC Chokes





16





Part Number E168-52 E168-52 E168-2




17








60

80

100

120

140

160

180

200

220

100 1000 10000 100000 1000000 10000000

Time (hours)


C )

PFC 1

PFC 2

PFC 3



18




Basic Design Rules









19

Conclusion





10










11





S R F 355 M H z 60 M H z















12







Thermal Aging




13






60

80

100

120

140

160

180

200

1000 10000 100000 1000000 10000000 100000000

Time (hours)





14








60

80

100

120

140

160

180

200

220

240

1000 10000 100000 1000000

Time (hours)


T90-26 75 kHz 633 G


MM - 55degC Ambient

MM - 61degC Ambient



15







PFC Chokes





16





Part Number E168-52 E168-52 E168-2




17








60

80

100

120

140

160

180

200

220

100 1000 10000 100000 1000000 10000000

Time (hours)


C )

PFC 1

PFC 2

PFC 3



18




Basic Design Rules









19

Conclusion





11





S R F 355 M H z 60 M H z















12







Thermal Aging




13






60

80

100

120

140

160

180

200

1000 10000 100000 1000000 10000000 100000000

Time (hours)





14








60

80

100

120

140

160

180

200

220

240

1000 10000 100000 1000000

Time (hours)


T90-26 75 kHz 633 G


MM - 55degC Ambient

MM - 61degC Ambient



15







PFC Chokes





16





Part Number E168-52 E168-52 E168-2




17








60

80

100

120

140

160

180

200

220

100 1000 10000 100000 1000000 10000000

Time (hours)


C )

PFC 1

PFC 2

PFC 3



18




Basic Design Rules









19

Conclusion





12







Thermal Aging




13






60

80

100

120

140

160

180

200

1000 10000 100000 1000000 10000000 100000000

Time (hours)





14








60

80

100

120

140

160

180

200

220

240

1000 10000 100000 1000000

Time (hours)


T90-26 75 kHz 633 G


MM - 55degC Ambient

MM - 61degC Ambient



15







PFC Chokes





16





Part Number E168-52 E168-52 E168-2




17








60

80

100

120

140

160

180

200

220

100 1000 10000 100000 1000000 10000000

Time (hours)


C )

PFC 1

PFC 2

PFC 3



18




Basic Design Rules









19

Conclusion





13






60

80

100

120

140

160

180

200

1000 10000 100000 1000000 10000000 100000000

Time (hours)





14








60

80

100

120

140

160

180

200

220

240

1000 10000 100000 1000000

Time (hours)


T90-26 75 kHz 633 G


MM - 55degC Ambient

MM - 61degC Ambient



15







PFC Chokes





16





Part Number E168-52 E168-52 E168-2




17








60

80

100

120

140

160

180

200

220

100 1000 10000 100000 1000000 10000000

Time (hours)


C )

PFC 1

PFC 2

PFC 3



18




Basic Design Rules









19

Conclusion





14








60

80

100

120

140

160

180

200

220

240

1000 10000 100000 1000000

Time (hours)


T90-26 75 kHz 633 G


MM - 55degC Ambient

MM - 61degC Ambient



15







PFC Chokes





16





Part Number E168-52 E168-52 E168-2




17








60

80

100

120

140

160

180

200

220

100 1000 10000 100000 1000000 10000000

Time (hours)


C )

PFC 1

PFC 2

PFC 3



18




Basic Design Rules









19

Conclusion





15







PFC Chokes





16





Part Number E168-52 E168-52 E168-2




17








60

80

100

120

140

160

180

200

220

100 1000 10000 100000 1000000 10000000

Time (hours)


C )

PFC 1

PFC 2

PFC 3



18




Basic Design Rules









19

Conclusion





16





Part Number E168-52 E168-52 E168-2




17








60

80

100

120

140

160

180

200

220

100 1000 10000 100000 1000000 10000000

Time (hours)


C )

PFC 1

PFC 2

PFC 3



18




Basic Design Rules









19

Conclusion





17








60

80

100

120

140

160

180

200

220

100 1000 10000 100000 1000000 10000000

Time (hours)


C )

PFC 1

PFC 2

PFC 3



18




Basic Design Rules









19

Conclusion





18




Basic Design Rules









19

Conclusion





19

Conclusion



AppNote uMetals Comparison and Examples Iron Powder Cores

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Transcript of AppNote uMetals Comparison and Examples Iron Powder Cores