Inductors

Token's high Q chip RF inductors are designed for resonant circuit applications requiring exceptionally high Q's and tight tolerances on inductance specifications. Chip RF Inductors can be customed designs and tighter tolerances available on request. Application of RF Inductors specific designs also available including different inductance values and Q specifications adjusted to frequency requirements.

Token Choke Coils of Surface Mount Device SMD inductor is primarily designed for choking power lines and conforms to the RoHS directive lead-free. SMD Choke coils has good heat durability that withstands lead-free compatible reflow soldering conditions. Token SMD Coils including: SMD common mode choke coils, SMD common mode EMI filters, and RFID transponder coils.

Token Electronics, a world leading innovator in inductor manufactures a full line of inductors, colis, magnetic products, which includes the most extensive offering of surface mount and lead type inductor. These devices are used in a wide variety of applications in a wide range of markets including networking, telecom, computers, switching power supply, and peripherals.

Inductors & Coils Application Notes

What is "Inductor"?

A passive component designed to resist changes in current. Inductors are often referred to as "AC resistors".

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Inductor Glossary

Inductors - Glossary Reference Page.

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Inductor Color Codes

Inductor color coding system applies coating inductors of the axial lead type.
This system is employed for inductors when the surface area is not sufficient to print the inductance value for the past time.

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Inductor Precautions in Use

Inductors - Precautions Usage.

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Tape and Reel Specifications for Surface Mount Inductors (Coils)

Tape and Reel Specifications of Surface Mount Multilayer Inductor, Ceramic Inductor, Chip Beads, Wirewound SMD Inductor, Chip Coils, and Choke Coils.

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RF Inductors - General Information

Token Cuts Inductor Size and Cost. How to quickly search RF inductors for all of the characteristics? Inductors Selection Notes.

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Technical Application Notes For Inductors And Chokes

Selecting The Optimum Indcutor Choke to Best Match The Right Performance. Comparision of Inductor Factors for Applications.

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SMD Wirewound and Power Inductors - General Information

How to Quickly Search Inductor for all of the Characteristics? Leading-Edge Technology. Find Inductor Solutions Faster.

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SMD Wirewound and Power Inductors - Application Notes

Selecting The Optimum Inductor Technology to Best Match The Performance Requirements. How to Select the Right Inductor for DC-DC Converter?

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Through Hole Inductors - General Information

Token Electronics brand passive component specializes in standard and custom solutions offering the latest in state-of-the-art low profile high power density inductor components. Token provides cost-effective, comprehensive solutions that meet the evolving needs of technology-driven markets.

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Magnetic Product Terminology & Glossary

Air Core Inductor, Axial Inductor, RF Choke, What is Inductor, DCR (DC Resistance), EMI, Ferrite Core, etc.

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Measurements of Fixed Inductors

Inductance, Q Factor, DCR (DC Resistance), SRF (Self-Resonant Frequency), Dielectric Strength, Maximum Allowable Current, Solderability, etc.

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Common Mode RF Components - General Information

In a RF balun transformer, one pair of terminals is balanced, that is, the currents are equal in magnitude and opposite in phase.
The other pair of terminals is unbalanced; one side is connected to electrical ground and the other carries the signal.

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What is Balun Transformer

What is Balun Transformer? Why Use a Balun? Insertion Loss (dB). Basics of Broadband Transformers.

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Inductors & Coils Electrical Specifications

Inductance

That property of a circuit element which tends to oppose any change in the current fl owing through it. The inductance for a given inductor is infl uenced by the core material, core shape and size, the turns count, and the shape of the coil. Inductors most often have their inductances expressed in microhenries (μH). The following table can be used to convert units of inductance to microhenries. Thus, 47 mH would equal 47,000 μH.

1 henry (H) = 106 μH
1 millihenry (mH) = 103 μH
1 microhenry (μH) = 1 μH
1 nanohenry (nH) = 10-3 μH

DCR (DC Resistance)

The resistance of the inductor winding measured with no alternating current. The DCR is most often minimized in the design of an inductor. The unit of measure is ohms, and it is usually specifi ed as a maximum rating.

Saturation Current

The DC bias current fl owing through the inductor which causes the inductance to drop by a specifi ed amount from the initial zero DC bias inductance value. Common specifi ed inductance drop percentages include 10% and 20%.

It is useful to use the 10% inductance drop value for ferrite cores and 20% for powdered iron cores in energy storage applications. The cause of the inductance to drop due to the DC bias current is related to the magnetic properties of the core.

The core, and some of the space around the core, can only store a given amount of magnetic flux density. Beyond the maximum flux density point, the permeability of the core is reduced. Thus, the inductance is caused to drop. Core saturation does not apply to "air-core" inductors. (Also see Incremental Current and Permeability)

Incremental Current

The DC bias current flowing through the inductor which causes an inductance drop of 5% from the initial zero DC bias inductance value. This current level indicates where the inductance can be expected to drop signifi cantly if the DC bias current is increased further.

This applies mostly to ferrite cores in lieu of powdered iron. Powdered iron cores exhibit "soft" saturation characteristics. This means their inductance drop from higher DC levels is much more gradual than ferrite cores.

The rate at which the inductance will drop is also a function of the core shape. (Also see Saturation Current).

Rated Current

The level of continuous DC current that can be passed through the inductor. This DC current level is based on a maximum temperature rise of the inductor at the maximum rated ambient temperature.

The rated current is related to the inductor's ability to minimize the power losses in the winding by having a low DC resistance. It is also related to the inductor's ability to dissipate this power lost in the windings.

Thus, the rated current can be increased by reducing the DC resistance or increasing the inductor size. For low frequency current waveforms, the RMS current can be substituted for the DC rated current. The rated current is not related to the magnetic properties of the inductor. (Also see Incremental Current and Saturation Current)

Permeability (Core)

The permeability of a magnetic core is the characteristic that gives the core the ability to concentrate lines of magnetic flux. The core material, as well as the core geometry, affect the core's "effective permeability".

For a given core shape, size and material, and a given winding, higher permeability magnetic materials result in higher inductance values as opposed to lower permeability materials.

SRF (Self-Resonant Frequency)

The frequency at which the inductor's distributed capacitance resonates with the inductance. It is at this frequency that the inductance is equal to the capacitance and they cancel each other. The inductor will act purely resistive, with a high impedance at the SRF point.

The distributed capacitance is caused by the turns of wire layered on top of each other and around the core. This capacitance is in parallel to the inductance. At frequencies above the SRF, the capacitive reactance of the parallel combination will become the dominant component.

Also, the Q of the inductor is equal to zero at the SRF point since the inductive reactance is zero. The SRF is specifi ed in MHz and is listed as a minimum value on product data sheets. (Also see Distributed Capacitance)

Distributed Capacitance

In the construction of an inductor, each turn of wire or conductor acts as a capacitor plate. The combined effects of each turn can be represented as a single capacitance known as the distributed capacitance. This capacitance is in parallel with the inductor.

This parallel combination will resonate at some frequency which is called the self-resonant frequency (SRF). Lower distributed capacitances for a given inductance value will result in a higher SRF value for the inductor and vice versa. (Also see SRF)

Q

The Q value of an inductor is a measure of the relative losses in an inductor. The Q is also known as the "quality factor" and is technically defi ned as the ratio of inductive reactance to effective resistance, and is represented by:

Q = \frac{XL}{Re} = \frac{2πfL}{Re}

Since XL and Re are functions of frequency, the test frequency must be given when specifying Q. XL typically increases with frequency at a faster rate than Re at lower frequencies, and vice versa at higher frequencies.

This results is a bell-shaped curve for Q vs frequency. Re is mainly comprised of the DC resistance of the wire, the core losses and skin effect of the wire. Based on the above formula, it can be shown that the Q is zero at the self-resonant frequency since the inductance is zero at this point.

Impedance

The impedance of an inductor is the total resistance to the fl ow of current, including the AC and DC component. The DC component of the impedance is simply the DC resistance of the winding. The AC component of the impedance includes the inductor reactance. The following formula calculates the inductive reactance of an ideal inductor (i.e., one with no losses) to a sinusoidal AC signal:

Z = XL = 2πfL

L is in henries and f is in hertz. This equation indicates that higher impedance levels are achieved by higher inductance values or at higher frequencies. Skin effect and core losses also add to the impedance of an inductor. (Also see Skin Effect and Core losses)

Operating temperature range

Range of ambient temperatures over which a component can be operated safely. The operating temperature is different from the storage temperature in that it accounts for the component's self temperature rise caused by the winding loss from a given DC bias current. This power loss is referred to as the “copper” loss and is equal to:

Power Loss = (DCR)(I2dc)

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Typical RoHS Reflow Profile

Typical RoHS Reflow Profile
Typical RoHS Reflow Profile

RoHS Reflow Profile

All Token RoHS-compliant parts are backward compatible with tin-lead soldering processes. Soldering temperature must be greater than 230°C to ensure proper melting of lead-free solder.

For all soldering methods, the optimal reflow profile for a circuit board assembly is dependent on the solder material, solder amount, flux, temperature limit of each soldered component, heat transfer characteristics of the circuit board and component materials, and the layout of all components.

The temperature versus time limitation of the least robust component of the circuit board assembly ultimately may determine the actual temperature profile that must be used. For these reasons, Token does not specify soldering profiles for our components.

This typical reflow profile is based on IPC/JEDEC J-STD-020 Revision D.1 (March 2008). It is provided only as a guide.

For additional information, refer to these web sites: www.jedec.org.

Soldering through-hole components

All our RoHS-compliant parts are backward compatible with tin-lead soldering processes.
For all soldering methods, the optimal soldering profile for a circuit board assembly is dependent on the solder material, solder amount, flux, temperature limit of each soldered component, heat transfer characteristics of the circuit board and component materials, and the layout of all components.

The temperature vs. time limitation of the least robust component of the circuit board assembly ultimately dictates the optimal temperature profile. For this reason, Token does not provide soldering profiles for our components.

Soldering surface mount components

All our RoHS-compliant parts are backward compatible with tin-lead soldering processes.
Soldering temperature must be greater than 230°C to ensure proper solder melting.

For all soldering methods, the optimal reflow profile for a circuit board assembly is dependent on the solder material, solder amount, flux, temperature limit of each soldered component, heat transfer characteristics of the circuit board and component materials, and the layout of all components.

The temperature versus time limitation of the least robust component of the circuit board assembly ultimately may determine the actual temperature profile that must be used. For these reasons, Token does not specify soldering profiles for our components.

A typical reflow profile based on IPC/JEDEC J-STD-020 Revision D.1 (March 2008) is provided only as a guide.

CAUTION:

All of Token’s through-hole components are designed to be wave soldered and it is not recommended to use a reflow soldering procedure. The higher temperatures of reflow soldering may damage these components.

Token’s through-hole components can be successfully wave soldered as long as care is taken throughout the process. For many of the components, it is essential to minimize the circuit board temperature and the time spent over the solder nozzle.

In order to achieve a quality bond without damaging the components, Token recommends preheating the board for up to three minutes and limiting the time the board spends over the solder nozzle to three seconds.

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Inductance and Inductance Tolerance Table

Inductance Table

nH µH SAP
11N0
1.21N2
1.51N5
1.81N8
2.22N2
2.72N7
3.33N3
3.93N9
4.74N7
5.65N6
6.86N8
8.28N2
100.0110N
120.01212N
150.01515N
180.01818N
220.02222N
270.02727N
330.03333N
390.03939N
470.04747N
560.05656N
680.06868N
820.08282N
1000.1R10
1200.12R12
1500.15R15
1800.18R18
2200.22R22
2700.27R27
3300.33R33
3900.39R39
4700.47R47
5600.56R56
6800.68R68

nH µH SAP
8200.82R82
11R0
1.21R2
1.51R5
1.81R8
2.22R2
2.72R7
3.33R3
3.93R9
4.74R7
5.65R6
6.86R8
8.28R2
10100
12120
15150
18180
22220
27270
33330
39390
47470
56560
68680
82820
100101
120121
150151
180181
220221
270271
330331
390391
470471
nH µH SAP
560561
680681
820821
1000102
1200122
1500152
1800182
2200222
2700272
3300332
3900392
4700472
5600562
6800682
8200822
10 000103
12 000123
15 000153
18 000183
22 000223
27 000273
33 000333
39 000393
47 000473
56 000563
68 000683
82 000823
100 000104
120 000124
150 000154
180 000184
220 000224
270 000274
330 000334

Inductance Tolerance Table

B C S D F G H
± 0.15 nH ± 0.2 nH ± 0.3 nH ± 0.5 nH ± 1 % ± 2 % ± 3 %
J K L M V N  
± 5 % ± 10 % ± 15 % ± 20 % ± 25 % ± 30 %  

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