WO2001027946A1

WO2001027946A1 - Interface module for a local data network

Info

Publication number: WO2001027946A1
Application number: PCT/EP2000/009882
Authority: WO
Inventors: Johannes Beichler; Johannes Binkofski; Ralf Heindel; Dirk Heumann; Harald Hundt; Jörg PETZOLD; Norbert Preusse; Ulrich PÜTZ
Original assignee: Vacuumschmelze Gmbh
Priority date: 1999-10-11
Filing date: 2000-10-09
Publication date: 2001-04-19
Also published as: DE19948897A1; EP1221169A1

Abstract

The invention relates to an interface module for a local data network comprising a series of inductive components (7,8) which connect the interface circuit (3, 4) to a data line (6). Said inductive components and in particular the translator (8) have a magnetic core (9) constructed from amorphous or nanocrystalline alloys and are characterized by a particularly small construction volume.

Description

description

Interface modules for local data networks

The invention relates to an interface module for local data networks with at least one inductive component for coupling interface circuits to a data line used to connect computers.

Such modules are also referred to as A modules. So far, ring cores made of highly permeable ferrite material (typically μ = 5000) have been used for transformers and chokes in LAN interface modules. In order to achieve the required main inductance with I _DC = 8mA, the number of turns for ferrites must be high, typically 20 to 40 turns for 100 Mbit / s Ethernet transmitters. The high number of turns leads to manufacturing disadvantages, for example when designing the transformers using planar technology. In addition, LAN interface modules with ferrite cores take up a lot of space.

Furthermore, it is a requirement for LAN interface modules that the main inductance maintains its value even with a maximum direct current preload of 8 mA in a temperature range from -40 ° C to 85 ° C, but preferably up to 120 ° C. However, the permeability of the ferrites mentioned at the outset, in particular the MnZn ferrites, fluctuates in the temperature range from -40 ° C. to 120 ° C. in some cases by more than +/- 40%. These fluctuations are undesirable.

It is therefore an object of the present invention to provide interface modules with at least one inductive component which is suitable for use in local data networks and has a small structural volume and an outstanding la

excellent temperature stability of permeability in a temperature range from -40 ° C to 120 ° C.

According to the invention, the task is solved by an inductive component with a magnetic core made of an amorphous cobalt-based alloy or a nanocrystalline iron-based alloy, which have permeabilities μ> 30000.

Typically, the main frequency range extends from local data networks to 10 MHz (10 Mbit / s Ethernet) or up to 125 MHz (100 Mbit / s Ethernet) or even higher in the case of Gigabit Ethernet. As mentioned above, the use of ferrite cores helps to achieve the required level of indication

I _DC up to 8mA high number of turns necessary. These lead to high coupling and winding capacities as well as a large leakage inductance. These influences have a negative impact on the pulse shape, due to overshoots and long rise and fall times.

Although it is possible to set the permeability very high in the case of amorphous and nanoknstall alloys by a corresponding manufacturing process, this has the consequence that the magnetic cores easily go into saturation. However, amorphous and nanocrystalline alloys can also be adjusted to average permeability values in the range from 12,000 to 80,000 and generally have a high degree of saturation. With nanocrystalline and amorphous alloys, it is therefore possible to coordinate the geometric dimensions of a magnetic core, its permeability and the number of turns so that small designs are possible. It should be particularly emphasized that the number of turns can be set to optimal values, so that there is at the same time a low leakage inductance and winding capacity. This means that amorphous and nanocrystalline magnetic cores can be used to create interface modules that meet the requirements for the signal form in accordance with standards and are also characterized by a particularly small construction volume and the possibility of cost-effective production using planar technology.

Alloys which are particularly suitable for use in interface modules for local data networks are the subject of the dependent claims.

The invention is explained in more detail below with reference to the attached drawing. Show it:

1 shows an overview of part of a local data network; Figure 2 shows an embodiment of a circuit of inductive components in an interface module;

Figure 3 is a diagram showing the dependency of the real part of the permeability in the serial equivalent circuit diagram for a nanocrystalline alloy and a ferrite;

Figure 4 is a diagram showing the dependence of the inductance in the parallel equivalent circuit diagram of a coil with a nanocrystalline magnetic core and a coil with a ferrite core on the direct current load;

FIG. 5 shows the temperature dependency of the permeability of amorphous and nanocrystalline alloys in comparison to the temperature dependence of the permeability of ferrites;

FIG. 6 shows the frequency response of the real part of the permeability of a nanocrystalline alloy compared to a ferrite;

FIG. 7 shows the frequency response of the inductance in the parallel replacement circuit diagram for a coil with a magnetic core made of a nanocrystalline alloy and for coils of ferrite cores;

FIG. 8 shows the frequency response of the ohmic resistance in the parallel equivalent circuit diagram for a magnetic core made of a nanocrystalline alloy;

FIG. 9 shows the frequency response of the insertion loss that can be achieved with the nanocrystalline magnetic core from FIGS. 7 and 8; and Figure 10 shows an example of a flat hysteresis loop of a magnetic core made of a nanocrystalline alloy.

Local data networks or LANs (Local Area Networks) are used to connect computers (PCs, workstations, mainframes) for data transmission over short distances. A distinction is made between LANs according to transmission standards (IEEE 802.3, Ethernet, IEEE 802.4 (Token Bus), IEEE 802.5 (Token Ring), transmission rates (e.g. 10 MBit / s, 100 MBit / s for Ethernet) and physical transmission medium (RG58 coaxial cable, twisted pair , Fiber optic, etc.) Computers can be interconnected via different topologies (star, bus, ring), thereby, as shown in FIG. 1, central units 1 such as hubs, switches, bridges and routers and network cards 2 (NICs = Network Interface Cards) m are required for the transmission of the data of the physical layer to these devices and cards, a logic module 3 (module for the physical layer) is used, either directly or via a transmitter-receiver module 4 (transceiver ) is coupled to a LAN interface module 5. This LAN interface module 5 then establishes the connection to a data line 6.

An exemplary embodiment of the interface module 5 is shown in FIG. The interface module 5 in FIG. 2 comprises a transformer 7, as well as current-compensated chokes 8, which each have magnetic cores 9. The magnetic cores 9 can be made of the same or different material. In addition to the components shown in FIG. 2, the interface module can have further inductive components such as transformer, throttle and filter components.

In the following, we restrict ourselves to LAN interface modules 5 for 10 MBit / s and LOOMBit / s.

Ethernet as systems representative of all these LAN technologies. The main frequency range of the signals is <10 MHz for 10 Mbit / s Ethernet and <125 MHz for 100 Mbit / s Ethernet. With the LAN

Interface modules 5, however, higher transmission rates (e.g. for Gigabit Ethernet) are also conceivable.

The following requirements are placed on the inductive components used in the LAN interface module 5: a) minimum construction volume b) suitability for the various transmission code systems, for example. MLT3 (100 Mbit / s). 4B5B (100 Mbps). Manchester coding (10 Mbit / s) c) For 100 Mbit / s Ethernet, the following must apply in accordance with ANSI X3.263-95 §9.1.7: Main inductance> 350 μH at 100 kHz, 100 mVr s and 0 A <I _DC < 8mA d) For 100 Mbit / s Ethernet, according to ANSI X3.263-95 §9.1.7 for the rise time t _A r.stιeg and the fall time

The impulses are: 3ns <t _Ans tιeg / tAbfaii <5ns f) low core weight and SMD capability g) toroidal shape, thereby simpler security requirements according to IEC 950 h) low insertion loss and high reflection attenuation (for 100 Mbit / s Ethernet according to ANSI X3. 263-95 §9.1.5) in the entire frequency range i) low and monotonous temperature response of the relevant magnetic parameters in the range -40 ° C - 100 ° C.

The inductive components presented here are inductive components for the LAN interface module 5, which contain the magnetic core 9 in the form of a small metal band core made of an amorphous or nanocrystalline alloy instead of a ferrite core. This receives its standard-compliant properties through an optimized combination of strip thickness, alloy and heat treatment in the magnetic field as well as core technological manufacturing steps. A first basic requirement is that the inductance of the LAN transmitter 7 is greater than 350 μH at 100 kHz. This must be ensured in the entire temperature range from 0 to 70 ° C or even from -40 ° C to + 85 ° C, possibly even from -40 ° C to + 120 ° C, with a direct current of up to 8 mA. 3, 4 and 5 show, this requirement was met with a correctly coordinated alloy, core dimension and winding, for example with nanocrystalline, but also with amorphous alloys.

FIG. 3 is a diagram in which the real part of the permeability is plotted in the serial equivalent circuit diagram against the strength of the constant field. The solid curve shows the dependence of the real part of the permeability of the nanocrystalline alloy (FeCuNb) 77.5 (SiB) _22/5 , while the dashed curve shows the dependence of the real part of the permeability of a MnZn ferrite with the trade name ("Ferronics B ") implies.

Figure 4 shows the ideal inductance of the transformer 7 as a function of the DC bias. The solid curve represents the inductance of the transformer 5 with the magnetic core 9 made of the nanocrystalline alloy (FeCuNb) 77, ₅ (SiB) ₂₂ , ₅ with an initial permeability μ_ (p) = 40,000 and 9 turns. The dashed line is the ideal inductance of a transmitter with an MnZn ferrite core (“Ferronics B”) with an initial permeability of] x _x - 5000 and 20 turns. From FIG. 4 it can be seen that the transmitter 5 with the magnetic core 9 made of the nanocrystalline alloy meets the requirements despite the small number of turns fulfilled much better than the transformer with the ferrite core.

FIG. 5 shows the relative change in permeability based on the permeability at room temperature in percent for different materials. A first steeply rising curve represents the temperature change of a MnZn ferrite with the trade name "Siferrit N27". The permeability of a further MnZn ferrite ("Ferronics B") fluctuates in the temperature range from -40 to 120 ° C by more than +/- 40%. The relative change in permeability for the nanocrystalline Fe7 _3.5 CuιNb ₃ Siιs, ₅ B ₇ and the amorphous (CuFi) ₇₂ (MuMnSiB) _2B , however, is in the range of +/- 20%.

6 and 7 that, in contrast to those with a ferrite core, no resonances occur in the case of a LAN transformer 5 with a metal band core (FIG. 6), and that resonances caused by the winding capacity are only at the top due to the lower number of turns Edge of the signal spectrum (Fig. 7) and thus - compared to ferrite - result in a smaller phase shift of the signals. This can affect the effective bit rate since fewer bit errors have to be corrected by the transmission protocols used.

A second basic requirement is that the insertion loss a _{E of} the transmitter 7 is as low as possible over the entire frequency range. With the magnetic cores 9 presented here, a _E values of well below 1 dB can be achieved at f> 100 kHz. For a given characteristic impedance (here: 100 Ω) the insertion loss decreases with increasing value for R _p . R _p is the ohmic resistance in the parallel equivalent circuit diagram for the transformer 7, which represents the remagnetization losses in the magnetic core 9 and the ohmic copper losses of the winding. On the basis of electrodynamics, the relationship p _mec h can be related

R _p (f) = 2 * π ^r N ^ * 1 / Pmech J (A _Fe / l _Fe ^ * B 7P _Fe ⁽ f

derive, where Pre (f) represents the frequency response of the specific total losses, which in turn depend on the hysteresis and the band properties. At the frequencies considered here of more than 100 kHz and extremely linear hysteresis loops, however, only play 8th

band-dependent eddy current losses and gyromagnetic effects play a role.

As can be seen from FIGS. 8 and 9, with the heat-treated magnetic alloys used here, sufficiently small a _ε or sufficiently large R _p values can also be achieved with the low number of turns sought here. As can also be easily understood from equation (2), particularly high R _p values can be achieved with the lowest possible strip thicknesses of <20 μm, better <17 μm or, if possible, even <14 μm. The R _p value can be further improved by coating at least one strip surface with an electrically insulating medium, which must have a small dielectric number of ε _r <10.

A third basic requirement is that the leakage inductance L _{s of} both the transformer 7 and the current-compensated chokes 8 is as small as possible. This is based on the requirements of ANSI X3.263 1995 points 9.1.3. (Flooding of the signal), 9.1.6. (Rise times of the signal) and 9.1.5. (Reflection loss requirements). A large leakage inductance causes an overshoot and a long rise time of the signal. At higher signal frequencies, the reflection attenuation is reduced by a large scattering ductility. Because of the core geometry used

(Rmgbandkern) and the low number of turns possible due to high permeability - in contrast to ferrites - very small scattering conductivities can be achieved.

In summary, it can be said that the combination of a flat hysteresis loop and significantly higher permeability μ and saturation reduction B _s compared to ferrite solutions when using thin bands of the heat-treated alloys used here with high specific electrical resistance inductors for LAN

Have joints made with particularly low numbers of turns and small size. In the studies on which it is based, it was recognized that the standard-compliant properties of the small magnetic cores 9 of inductors used in the LAN interface modules can be achieved with amorphous, almost agnetostriction-free cobalt-based alloys and with practically magnetostriction-free fine-crystalline alloys. The latter are usually referred to as "nanocrystalline alloys" and are characterized by an extremely fine grain with an average diameter of less than 100 n, which takes up more than 50% of the material volume. An important requirement is that the magnetic cores 9 have a high saturation induction of B _s > 0.55 T, preferably> 0.9 T, better> 1 T and a linear hysteresis loop with a saturation to remanence ratio B _r / B _s < 0.2, preferably

Have <0.08. In this context, the magnetostriction-free nanocrystalline materials based on Fe are characterized by a particularly high saturation induction of 1.1 T or more. A list of all considered and suitable alloy systems can be found below. A typical loop shape can be seen in FIG. 10. Such a hysteresis loop can be achieved, for example, by the production steps described below:

The soft magnetic amorphous tape of thickness d <22 μm, preferably <17 μm, better <14 μm, produced from one of the alloys listed below, which is produced by means of rapid solidification technology, is wound stress-free to the magnetic core 9 in its final dimension on special machines. Alternatively, magnetic cores 9, which are constructed from a stack of punched disks made of said alloys, are also possible.

It has been found that the standards-compliant requirements for the frequency properties can be met even better if the tape is wound on one or on two sides before the magnetic core 9 is wound or before the disks are punched 10

is coated electrically insulating. Depending on the alloy, heat treatment and requirements for the quality of the insulation layer, an oxidation, immersion, continuous, spray or electrolysis process is used for this. The same can also be achieved by dip insulation of the wound or stacked magnetic core 9. When selecting the insulating medium, care must be taken to ensure that it adheres well to the surface of the tape and does not cause any surface reactions that could damage the magnetic properties. In the alloys used here, oxides, acrylates, phosphates, silicates and chromates of the elements Ca, Mg, Al, Ti, Zr, Hf, Si have proven to be effective and compatible insulators. Particularly effective, but nonetheless gentle, was Mg, which is applied to the strip surface as a liquid magnesium-containing preliminary product and, during a special heat treatment that does not affect the alloy, is converted into a layer of MgO, the thickness of which can be between 50 n and 1 μm ,

In the subsequent heat treatment of the insulated or uninsulated magnetic cores 9 for setting the soft magnetic properties, a distinction must be made as to whether the magnetic core 9 consists of an alloy which is suitable for setting a nanocrystalline structure or not.

Magnetic cores 9 made of alloys which are suitable for nanocrystallization are subjected to a precisely coordinated crystallization heat treatment for adjusting the nanocrystalline structure, which is between 450 ° C. and 690 ° C. depending on the alloy composition. Typical holding times are between 4 minutes and 8 hours. Depending on the alloy, this heat treatment can be carried out in a vacuum or in a passive or reducing protective gas. In all cases, material-specific cleanliness conditions must be taken into account, which can be brought about by appropriate aids such as element-specific absorber or getter materials. Doing so 11 exploited by an exactly balanced combination of temperature and time, that in the alloy compositions used here, described in more detail below, the magnetostriction contributions of fine-crystalline grain and amorphous residual phase compensate and the required freedom from magnetostriction (I λ _s | <2 ppm, preferably even | λ _s | <0.2 ppm) arises. The high permeabilities required here require these particularly precisely matched magnetostriction values and thus a particularly precisely adjusted particle size distribution and thus alloy composition. It is important to precisely control the magnetic core temperature in the area of crystal formation. Under no circumstances should the material be heated to such an extent that the formation of non-magnetic phases such as Fe boride causes irreversible damage to the magnetic properties.

Depending on the alloy and embodiment of the component, annealing is carried out either in a field-free manner or in a magnetic field along the direction of the wound strip (“longitudinal field”) or transversely thereto (“transverse field”) in order to achieve high permeability values. In certain cases, a combination of two or even three of these magnetic field constellations may be necessary in succession or in parallel.

If necessary, the magnetic properties, ie the linearity and the slope of the hysteresis loop, can be varied widely by an additional heat treatment in a magnetic field that is parallel to the axis of rotation symmetry of the magnetic core 9 - that is, perpendicular to the band direction. Depending on the alloy and the permeability level to be set based on dimensions, temperatures between 350 ° C and 690 ° C are required. Due to the kinetics of the atomic reorientation processes, the lower the cross-field temperature, the higher the resulting permeability values. This magnetic field heat treatment is either combined directly with the crystallization heat treatment or carried out separately. For the glowing atmosphere 12

the same conditions apply as for the tempering to adjust the nanocrystalline structure.

In the case of magnetic cores 9 made of amorphous materials, the magnetic properties, ie the shape and gradient of the linear flat hysteresis loop, are created by a heat treatment in a magnetic field that runs parallel to the axis of symmetry of the magnetic core 9 - that is, perpendicular to the band direction. Favorable management of the heat treatment takes advantage of the fact that the value of the saturation agnostriction changes during the heat treatment in a positive direction, depending on the alloy composition, until it reaches the range λ _s | <2 ppm, preferably even | λ _s | <0.05 ppm hits. As Table 2 shows, this was also achieved if the amount of λ _s in the as quenched state of the strip was significantly above this value. Depending on the alloy used, it may be necessary to rinse the magnetic core 9 with a reducing (for example NH ₃ , H ₂ , CO), passive or even weakly oxidizing protective gas (for example He, Ne, Ar, N ₂ , C0 ₂ ), so that the band surfaces neither

Oxidation or other reactions can occur. Nor can solid-state physical reactions due to diffusing protective gas be allowed to take place inside the material.

Depending on the position of the Curie temperature and crystallization temperature of the alloy used, the magnetic cores 9 for the inductances used in the LAN interface modules 5 can be applied at a rate of 0.1 to 10 K / mm to temperatures between 180 ° C. and 420 ° under an applied magnetic field C are heated, kept at these temperatures in the magnetic field between 0.25 and 48 hours and then cooled back to room temperature with 0.1 - 5 K / mm. Due to the general relationships K ^Q CM _s (T _a ) ² and K _u oc 1 / μ (K _u = anisotropy energy, M _Ξ = saturation magnetization, T _a = tempering temperature in the magnetic field) are the achieved

With the amorphous alloys used here, the flatter the flatter the higher M _Ξ . So you are one 13

Dilemma in which high permeabilities and high saturation induction, which are indispensable for high asymmetry currents, are mutually exclusive.

Particularly small magnetic cores 9 for LAN transmitters 7 can be achieved if the amorphous alloys used on the one hand have low Curie temperatures of, for example, less than 250 ° C., but on the other hand still have a sufficiently high saturation induction of, for example, 0.65 Tesla or more. Such, in principle, contradictory combinations can be achieved by gradually increasing the metalloid content (eg Si, B etc.) of the alloy and / or at the same time adding an antiferromagnetic element such as Mn in the range of less at% of the alloy. As a result of small magnetic moments with a simultaneous temperature-related delay in the reorientation kinetics, particularly small uniaxial (transverse) anisotropies of only 1 J / m ³ or even less and thus permeability values of, for example, 20,000 to 200,000 can be achieved below the Curie temperature by means of defined cooling in the transverse field ,

An important prerequisite for achieving such high permeabilities is that any kind of interference terms such as magnetoelastic anisotropies are negligible compared to the desired magnetic field-induced anisotropies. To meet this requirement, the wound magnetic core 9 in the form of a metal strip core must be relaxed by means of a relaxation anneal even at the smallest magnetostriction values. The temperature required for this is to be set so high that the relaxation kinetics on the one hand proceed sufficiently quickly, but on the other hand no crystallization occurs yet. This procedure is particularly effective when the crystallization and Curie temperatures are far more than 100 ° C apart, which is the case with the amorphous alloys with high metalloid content used here. 14

In some cases, in order to increase the uniaxial anisotropy energy, in addition to slowly cooling the magnetic cores 9 in the transverse field, a temperature plateau can be inserted in the transverse field. Following the known influences of temperature dependency of the magnetization of the saturation and reflecting kematics, the optimal distance to the Curie temperature and the holding time until the equilibrium value of the uniaxial anisotropy is reached asymptotically are the decisive parameters that have to be adapted to the respective alloy.

Due to the demagnetizing fields inside a magnetic core stack, which lead to a weakening of the amount and a divergence of the field lines, even with high permeability values, sufficiently linear loops can be achieved in that the magnetic cores 9 are stacked on the face side during the cross-field treatment in such a way that the stack height is at least is 10 times, better at least 20 times the outer diameter of the magnetic core. This applies in the same way to nanocrystalline as to amorphous magnetic materials. A typical magnetization curve that underlines the linear character of the loops realized here can be seen in FIG. 10.

Following the heat treatment, the magnetic cores 9 are electrically insulated (for example surface passivated, coated, whirl sintered or encapsulated in a plastic housing), provided with the primary and secondary windings and, if appropriate, glued or cast in the component housing. It is also possible to use a structure in so-called planar technology. This method is independent of whether the magnetic core 9 consists of amorphous or nano-crystalline material. Due to the brittleness, however, the mechanical handling of the tempered nanocrystalline magnetic cores 9 must be carried out with particular care. 15

Another manufacturing possibility is that the strip is first subjected to a cross-field tempering in the run and then wound into the strip core. The rest of the process proceeds as described above. The essential requirements for 10 / 100Base-T transmitters are:

- According to ANSI X3.263 1995, the main inductance of the magnetic core 9 in the form of a wound metal strip core must meet the following condition:

- For the resistor R _p in the parallel equivalent circuit diagram, sufficiently high values of over> lkΩ can be achieved even with small numbers of turns.

- The main inductance fulfills this value even with a maximum direct current preload of 8 mA in a temperature range from -40 ° to 85 ° C, when using nanocrystalline alloys also up to 120 ° C.

The error in the hysteresis loop of the magnetic core 9 is so small that the ratio of permeability μ to the mean permeability μ is in the range

Bs / 100 to 0.8 B _s applies: 1.2> μ (B) / μ> 0.8, preferably 1.1> μ (B) / μ> 0.9, B likewise in the interval B _s / 100 to 0.8 B ₃ .

- Using amorphous and nanocrystalline magnet materials, the cross-section tempering for predetermined values of the main inductance results, for example, in the typical dimensions of the magnetic core 9 shown in Table 1, the dimensions being in the order of the outside diameter, inside diameter and height of the ring ring core present magnetic core 9 are specified. 16

Similar dimensions of the magnetic core 9 also result when using the other alloys listed below, which are used for specific applications.

When dimensioning the inductive components of the interface module 5, in particular the transformer 7, a number of relationships must be taken into account.

The relationship applies to the inductance of the transformer 7

L = N ² μ ₀ μ _r A _fe / lfe

N = number of turns μ ₀ = universal permeability constant μ _r = permeability of the material

A _fe = iron cross section of the magnetic core l _f e = iron path length of the magnetic core.

From equation (2) it can be seen that the required inductance can only be achieved with a minimal construction volume if the number of turns, permeability, iron cross-section and length of the iron path are coordinated. The permeability μ of the core material which is valid in the entire range of the working frequency is, in addition to the favorable annular geometry, the decisive parameter for the most compact possible dimension of the transmitter 7. Depending on which of the following 17

Alloys listed are used, and how the associated heat treatment is carried out, a permeability range between 10,000 and 100,000 can be covered in a defined manner. The LAN interface modules 5 realized with these magnetic cores 9 have a large volume advantage over the ferrite cores due to their design, the high permeability and the high saturation induction of the metal strip cores used.

When selecting the core material for the inductances of the transformer 7, a limitation arises because the magnetic core 9 must not saturate at the DC bias of 8 mA. Furthermore, the distortion factor at maximum I _dc modulation must remain below a limit set in accordance with the standard. The magnetic field strength H _DC associated with the I _dc preload is through

H _dc = N * I _dc / l _fe (3)

given. With this direct current preload, the inductance and the distortion factor may only decrease very slightly over the entire temperature range.

In contrast to the inductive components with ferrites, in which equation (2) specifies the number of turns, equation (1) is decisive for the dimensioning of inductive components with nanocrystalline or amorphous metal cores. The number of turns N must not be chosen too small, since otherwise the insertion loss will be too great due to the too low R _p resistance of the transformer 7. In addition, small numbers of turns result in high leakage inductances, which cause overshoot and a long rise time for the signal. An increase in the number of turns also leads to a smaller signal modulation B _ac and thus to a lower distortion factor. The transformer 7 therefore preferably has average turns between 5 and 25 turns. 18

When selecting materials, this situation requires a combination of high saturation reduction B _s , high permeability μ and low core losses (~ 1 / R _P ).

A high permeability and thus a low number of turns as well as the ring band shape of the magnetic cores 9 lead to small transformers 7 with a small leakage inductance and small coupling and winding capacitances. This in turn leads to shorter rise times, better asymmetry damping and improved transmission behavior in the entire frequency range.

Several suitable alloy systems are described below. It has been found that the alloy systems described below can be used to produce inductive components for the interface modules 5 with particularly linear hysteresis loops and small designs, all of which have properties that conform to the standards, while complying with the conditions mentioned above.

It should be noted that when specifying the alloy systems listed below, the small and large signs close the boundaries; in addition, all at% figures are to be regarded as approximate.

19

Alloy system 1:

A first alloy system has the composition Co _a (Fe _ι - _c Mn _c ) _b Ni _d M _e SiχB _y C _z , where M is one or more elements from the group Nb, Mo, Ta, Cr, W, Ge and / or P and a + b + d + e + x + y + z = 100, with

Co a = 40 - 82 at% preferably 55 <a <72 at%

Fe + Mn b = 3 - 10 at% Mn / Fe c = 0 - 1 preferably x <0.5

Ni d = 0 - 30 at% preferably d <20 at%

M e = 0-5 at% preferably e <3 at%

Si x = 0 - 18 at% preferably x> 1 at%

B y = 8 -26 at% preferably 8 - 20 at% C z = 0 - 3 at%

15 <e + x + y-t-z <30, preferably 20 <e + x + y + z <30

Alloys of this system remain amorphous after the heat treatment described. Depending on the composition and heat treatment, extremely linear hysteresis loops with a very wide permeability range between 500 and 150,000 or even more could be realized.

It has been found to be particularly important for the present invention that the value of the saturation magnetostriction with a heat treatment matched to the alloy composition certainly reaches particularly small values of | λ _s | <0.1 ppm can be set. This results in a particularly linear loop shape, which leads to a particularly high level of permeability over a wide induction range. In addition, the occurrence of harmful magnetoelastic resonances of the ring-shaped magnetic core 9 is thereby avoided. At certain frequencies of the induction curve, these led to drops in the permeability and / or to increased magnetic reversal losses. During the investigations it was found that the combination of this approximate magnetostriction-free 20 unit, the smallest possible band thickness (preferably less than 17 μm) and a comparatively high specific electrical resistance of 1.1 to 1.5 μΩm leads to an extremely good frequency response, which is particularly well suited for the transmitter 7.

Alloy system 2:

A second alloy system has the composition Fe _x Cu _y M _z SivBw, where M is an element from the group Nb, W,

Ta, Zr, Hf, Ti, Mo or a combination of these and x + y + z + v + w = 100 at%, with

Fe x = 100 at% - y - z - v - w Cu y = 0.5 - 2 at% preferably 1 at%

M z = 1 - 6 at% preferably 2 - 4 at%

Si v = 6.5 - 18 at% preferably 14 - 17 at%

B w = 5-14 at%, preferably 6-9 at%, where v + w> 18 at%, preferably v + w = 20 to 24 at%.

Alloys of this system have proven to be very suitable for the transformer 7 because of their linear loop shape and their very good frequency behavior. Particularly good properties are achieved in the alloy compositions highlighted as “preferred”, since here, just as in the alloy system 1, a zero crossing of the saturation magnetostriction can be set. It was also found here that the combination of a high specific electrical resistance from 1.1 to

1.2 μΩm and a small band thickness leads to excellent frequency behavior, which can be further increased by reduced band thicknesses of 14 μm or even less. As can be seen from FIG. 3, with optimally coordinated heat treatment at 100 kHz initial permeabilities of μi (100 kHz)> 25000 can be easily met, in the case of the In the 21st examinations, μi> 50,000 was observed in some cases.

In addition, the comparatively high saturation induction measured with B _s = 1.1 to 1.3 T has proven to be very advantageous in the case of extremely linear loops, since this results in a high stability against asymmetry currents. In addition, high values for the gyromagnetic cutoff frequency, which ultimately depends on B _s / μι, are achieved. The latter is an important prerequisite for high permeabilities in the MHz range. In addition, it was found that the temperature characteristic of the magnetic cores 9 can be specifically adjusted via the heat treatment to adjust the permeability. This can give rise to application-specific advantages that cannot be realized otherwise, particularly in harsh environmental conditions, such as can occur in telecommunications equipment.

Alloy system 3:

A third alloy system is composed according to Fe _x Zr _y Nb ₂ B _v Cu ", where x + y + z + v + w = 100 at%, with

Fe x = 100 at - y - z - v - w preferably 83 - 86 at%

Zr y = 2 - 5 at% preferably 3 - 4 at%

Nb z = 2 - 5 at% preferably 3 - 4 at%

B v = 5 - 9 at%

Cu w = 0.5 - 1.5 at%, preferably 1 at%, where y + z> 5 at%, preferably 7 at%, and y + z + v> 11, preferably 12 - 16 at%.

With alloys of this system, linear hysteresis loops with permeabilities between approx. 12,000 and more than 30,000 are also achieved by cross-field heat treatments, which are to be carried out alloy-specifically in the interval between 510 ° C and 680 ° C. With strip thicknesses around 15 μm 22

there are still initial permeabilities of almost 20,000 at 100 kHz and thus a good frequency response suitable for the inductive components in the interface module 5. Here too, the high saturation induction of 1.5 to 1.6 T has a particularly favorable effect on the size of the inductive component and the position of the gyromagnetic cutoff frequency. Particularly noteworthy is the very small saturation magnification, which is clearly below | λ _s | at tempering temperatures of around 600 ° C = 1 ppm.

Alloy system 4:

A fourth alloy system has the composition Fe _x M _y B _z Cu _w , where M denotes an element from the group Zr, Hf, Nb and x + y + z + w = 100 at%, with

Fe x = 100 at% - y - z - preferably 83 - 91 at% M y = 6 - 8 at% preferably 7 at% B z = 3 - 9 at%

Cu w = 0 - 1.5 at%.

With alloys of this system the basic requirement | λ _s | Meet <1 ppm. The permeabilities achievable with the cross-field treatments between 510 ° C and 680 ° C, depending on the alloy, lie between 2000 and 15000. The high saturation induction of 1.5 to 1.6 T also allows the implementation of very small interface modules 5.

Alloy system 5:

A fifth alloy system has the composition (Fe ₀ , ₉₈ Co ₀ , o ₂ ) ₉ o-χZr7B _{2 + x} CUι with x = 0 - 3, preferably x = 0, wherein Co can be replaced by Ni if the remaining alloy components are matched accordingly. 23

With this system, with cross-field heat treatment tailored to the alloy, a zero crossing in the saturation magnetostriction can also be achieved, which allows particularly linear hysteresis profiles with initial permeabilities of μi> 10000. This makes the frequency responses of the complex permeability so good that they come very close to those of alloy systems 1 and 2. The outstanding advantage of this system is the high saturation induction, which is around B _s = 1.70 T.

Due to the particularly favorable combination of almost no magnetostriction and high saturation induction, interface modules 5 can again be realized with particularly small designs.

After heat treatment, alloy systems 2 to 5 are given a fine crystalline structure with grain diameters below 100 nm. These grains are surrounded by an amorphous phase, which however takes up less than 50% of the material volume.

All alloy systems 1 to 5 are characterized by the following properties:

- very linear hysteresis loop.

- Amount of saturation magnetostriction \ λ _s \ <2 ppm, preferably <0.1 ppm after the heat treatment. In the case of the cobalt-based amorphous materials, this should be adjusted by appropriately adjusting the Fe and Mn content. In the case of the nanocrystalline alloys, the size of the fine-crystalline grain can be achieved through a targeted coordination of the heat treatment, the metalloid content and the content of refractory metals. 24

- Saturation reduction from 0.56 T - 1.7 T. The saturation reduction can be fine-tuned by choosing the content of Ni, Co, M, Si, B and C.

- belts, the thickness of which can be less than 17 μm

- High specific electrical resistance, which can be up to 1.5 μΩm.

Examples:

The requirements and alloy ranges mentioned above are fulfilled after performing the heat treatment described e.g. complied with or fulfilled by the alloy examples listed in Table 2.

tab2

The amorphous, distant or nanocrystalline alloys in Table 2 are characterized by particularly high saturation modulation values of up to 1.7 Tesla. These allow comparatively high permeability values, which gives advantages in terms of size and wrapping compared to remote transmitters.

Claims

25Patentansprüche

1. Interface module for local data networks with a serving as a transformer inductive component (7) for coupling interface circuits to a connection of computers serving data line, the inductive component having a magnetic core (9) and a plurality of windings applied thereon, characterized in that the inductive component (7) serving as a transformer has a magnetic core (9) made of an amorphous or nanocrystalline alloy with a permeability μ> 15000 and the number of turns of the windings is between 5 and 25.

2. Interface module according to claim 1, d a d u r c h g e k e n n z e i c h n e t that the amorphous or nanocrystalline alloy has a permeability μ> 30000.

3. Interface module according to claim 1 or 2, characterized in that the alloy has the composition Co _a (Feι- _c Mn _c ) _b Ni _d M _e Si _x B _y C _z , wherein M one or more elements from the group Nb, Mo , Ta, Cr, W, Ge and / or P and a + b + d + e + x + y + z = 100 at%, with

Co a = 40 - 82 at%

Fe + Mn b = 3 - 10 at%

Mn / Fe c = 0-1

Ni d = 0 - 30 at%

M e = 0 - 5 at%

Si x = 0 - 18 at%

B y = 8 -26 at%

C z = 0 - 3 at% and 15 at% <e + x + y + z <30 at% 26

4. Interface module according to claim 3, d a d u r c h g e k e n n z e i c h n e t that the relationships apply:

Co a = 55-72 at Mn / Fe c = 0-0.5

Ni d = 0 - 20 at% M e = 0 - 3 at% B y = 8 -20 at% Si x = 1 - 18 at% and 20 at% <e + x + y + z <30 at%

5. Interface module according to claim 1 or 2, characterized in that the alloy has the composition Fe _x Cu _y M _z Si _v B _w , where M is an element from the group Nb, W, Ta, Zr, Hf, Ti, Mo or one Combination of these and x + y + z + v + w = 100 at%, with

Fe x = 100 at% - y - z - v - w

Cu y = 0.5 - 2 at% M z = 1 - 6 at%

Si v = 6.5 - 18 at%

B w = 5 - 14 at%, where v + w> 18 at%.

6. Interface module according to claim 5, d a d u r c h g e k e n n z e i c h n e t that the relationships apply: Cu y - 1 at%

M z = 2-4 at% Si v = 14-17 at% where v + w = 20 to 24 at%.

7. Interface module according to claim 1 or 2, characterized in that the alloy has the composition Fe _x Zr _y Nb _z B _v Cu _w , where x + y + z + v + w = 100 at%, with Fe x - 100 at % - y - z - v - w 27

Zr y = 2 - 5 at%

Nb z = 2 - 5 at%

B v = 5 - 9 at%

Cu w = 0.5 - 1.5 at% where y + z> 5 at% and y + z + v> 11 at%.

8. Interface module according to claim 7, d a d u r c h g e k e n n z e i c h n e t that the relationships apply: Fe x = 83 - 86 at%

Zr y = 3-4 at%

Nb z = 3-4 at%

Cu w = 1 at% where y + z> 7 at% and y + z + v> 12 to 16 at%.

9. Interface module according to claim 1 or 2, characterized in that the alloy has the composition Fe _x M _y B _z Cu _w , where M denotes an element from the group Zr, Hf, Nb and x + y + z + w = 100 at % is with

Fe x = 100 at% - y - z - w M y = 6 - 8 at% B z = 3 - 9 at% Cu w = 0 - 1.5 at%.

10. Interface module according to claim 9, d a d u r c h g e k e n n z e i c h n e t that the relationships apply:

Fe x = 83 - 91 at% M y = 7 at%.

11. Interface module according to claim 1 or 2, characterized in that the alloy has the composition (Fe ₀ , 98Co ₀ , o ₂ ) 9o-χZr ₇ B _{2 + x} Cu _ι with x = 0 - 3 at%, with appropriate adjustment of the remaining alloy components Co can be replaced by Ni. 28

12. Interface module according to claim 11, d a d u r c h g e k e n n z e i c h n e t that x = 0 applies.