Cores amorphous with linear loop for transformers and chokes for ISDN networks

MSP series

MSP-series of high permeability magnetic cores with or without DC bias is designed for several types of pulse transformers in modern communication equipment for ISDN networks, local local area networks LAN, digital xDSL lines, modems, etc.

Pulse transformers and interface matching chokes for digital communication lines must have high permeability with the highest possible DC bias. Traditionally, Mn-Zn ferrite has been used as the main magnetic material for pulse transformers and interface chokes. However, in this case, due to the low permeability and, accordingly, low impedance, it is difficult to achieve small dimensions of the products. If an increase in impedance is achieved due to an increase in the number of winding turns, then the frequency characteristics deteriorate: the parasitic capacitance increases and the resonant frequency decreases. As a result, it is difficult to meet the requirements of the ITU-T I.430 standard.

The offered magnetic cores of the MSP series, made of a thin (25 µm) amorphous tape based on cobalt, provide small overall dimensions and excellent quality characteristics of pulse transformers and chokes for all ISDN interfaces: S2m, S0, Up0, Uk0; optimal for xDSL technologies and data line chokes.



The twisted tape magnetic core is placed in a rigid protective container made of glass-filled polyamide and mechanically fixed with silicone sealant. The container has rounded edges and is designed for direct wrapping. The container provides reliable mechanical protection of the amorphous material and the preservation of its properties. All materials comply with UL94V-1/0 standard.



  • High permeability with DC bias capability
  • Small overall dimensions
  • High impedance over a wide frequency range
  • Compliant with ITU-T I.430 standard
  • Low attenuation over a wide frequency range
  • Insulation requirements according to IEC 950, EN 60950, BS 601
  • Low losses
  • Reducing energy consumption in communication equipmen



S0 interface:

  • Communication between network (NT) and subscriber terminals (ST)
  • Communication between Automatic telephone station and Subscriber Terminals (ST)

Up0 / Uk0 interface:

  • Communication between local central office and network terminal (NT1)

Interface S2m:

  • Communication between the local central office and the Automatic telephone station


Recording example

MSP-10S-32, where:

  • P - application (telecommunications);
  • 10 - outer diameter, mm;
  • S - section symbol;
  • 32 - development code 



Core name Dimensions in the container (D-d-H), mm Centerline length Lm, mm The effect. section Ас, mm Coeff. ind-ty
АLo* (μH / turn2)
Coeff. ind-ty
АLdc** (μH / turn2)
Typical Application
Nominal Nominal Мin. Min.
MSP-10S-32 11,1-5,1-5,8 25,5 6,1 26,0 (a) - S2M
MSP-10B-30 11,1-5,3-7,6 25,5 8,2 20,7 (a) 14,1 (b) S0 (1mA)
MSP-10S-18 11,1-5,1-5,8 25,5 6,1 18,4 (a) 12,4 (c) S0 (3mA)
MSP-06A-12 6,8-3,0-4,1 15,0 3,8 9,8 (a) 6,9 (d) S0 (4mA)
MSP-10S-14 11,1-5,1-5,8 25,5 6,1 8,9 (a) 6,1 (e) S0 (5mA)
MSP-07A-08 7,5-3,0-4,2 15,9 5,2 - 0,6 (f) Upo, DSL
MSP-10S-03 11,1-5,1-5,8 25,5 6,1 - 0,315 (g) Uko, DSL
* - Минимальное значение начального коэффициента индуктивности при F=10Кгц, Urms=0,1B, T=25°C, ** - Мин. значение при подмагничивании постоянным током (Urms=0,1B, T=25°C)
(a) - Idc = 0, F = 10 kHz
(b) - Idc x N = 19 mA x turn, F = 20 kHz
(c) - Idc x N = 66 mA x turn, F = 20 kHz
(d) - Idc x N = 120 mA x turn, F = 20 kHz
(e) - Idc x N = 145 mA x turn, F = 20 kHz
(f) - Idc x N = 4500 mA x turn, F = 10 kHz
(g) - Idc x N = 10.2 A x turn, F = 10 kHz