TAK Technology
M61
HIGH FREQUENCY STABLE MATERIALS
M61 is a NiZn ferrite with an initial permeability (μi) of approx. 100, a saturation flux density (Bs) of approx. 340 mT at 25 °C (280 mT at 100 °C) and a Curie temperature above 300 °C. Its signature is temperature stability: a temperature coefficient of about −2×10⁻⁶/K — essentially zero — together with the >300 °C Curie point keeps inductance and impedance nearly drift-free over a wide temperature span, while losses stay low below 20 MHz. As an EMI-suppression material its normalized impedance is measured on an RH5×1.5×10 bead (curve on the next page). Typical uses are mid-frequency inductors, EMI common-mode chokes and filter elements in RF power modules, as well as bead-type EMI suppression. M61H shares the same μi ≈ 100 despite the similar name: M61 leads in near-zero drift, M61H (Bs approx. 420 mT) in power capability — pick M61 for temperature stability, M61H for high current.
Magnetic Characteristics
| Characteristic | Condition | Value | Unit |
|---|---|---|---|
| μiInitial Permeability | 100 kHz & <0.2 mT | 100±25% | — |
| BsSaturation Flux Density | 3000 A/m · 25 ℃100 Hz | 340 | mT |
| BsSaturation Flux Density | 3000 A/m · 100 ℃100 Hz | 280 | mT |
| BrRemanence | 3000 A/m · 25 ℃100 Hz | 220 | mT |
| BrRemanence | 3000 A/m · 100 ℃100 Hz | 180 | mT |
| HcCoercivity | 3000 A/m · 25 ℃100 Hz | 400 | A/m |
| HcCoercivity | 3000 A/m · 100 ℃100 Hz | 200 | A/m |
| αμrTemperature coefficient of permeability | 20～60 ℃ | -2 | ×10⁻⁶/K |
| tanδ/μiRelative Loss Factor | 1.0 MHz & <0.2 mT | 80 | ×10⁻⁶ |
| tanδ/μiRelative Loss Factor | 5.0 MHz & <0.2 mT | 100 | ×10⁻⁶ |
| TcCurie Temp. | 100 kHz & <0.2 mT | >300 | ℃ |
| DDensity | Archimedes method | 4.9 | g/cm³ |
| ρVolume Resistivity | DC Current | 10⁷ | Ω·m |
Characteristic curves
Applications
| Application | Role | Band | Temperature |
|---|---|---|---|
| Temperature-stable filter / tuning inductor (low αμr) | Alternative | ≤6 MHz | — |
| Wideband signal transformer / balun | First choice | ≤7.7 MHz | — |
| Antenna rod / RFID / high-Q inductor | First choice | 0.2–6.2 MHz | — |
| Low-μ tuning / HF resonance | First choice | 0.2–6.2 MHz | — |
| EMI bead / ring / cable sleeve | Alternative | 100–300 MHz | — |