Material selection by application

FIG · POWER-FERRITE MAP ⤢

How to read

Further right = higher usable frequency at the same loss threshold; higher up = larger DC-bias margin; a longer line = larger Bs derating with temperature. High-frequency DC-DC (VRM / TLVR) requires a high threshold frequency and sufficient Bs at the 100 °C end; PFC and main transformers prioritise Bs and low-frequency loss.

The six classes

From left to right the six classes follow their bands: low-frequency high-Bs (≈0.1 MHz) → standard band (three TP and three wide-temperature grades, threshold 0.5–1 MHz) → mid-frequency TM50A / TM59★ → MHz band TM61 / TM65★ → ultra-high-frequency TM63 (2 MHz); the high-Bs special grades TM71 / TM82 excel in Bs, not threshold frequency. ★ = recommended in the VRM / TLVR selection guide.

No extrapolation

Grades marked “≥” have a threshold beyond the fitted range of their loss model; the map clips at the fit limit instead of extrapolating, so the real capability may be higher. Dashed lines have no 50 mT loss data and are placed by class band; their capability is assessed by the IDC comparison.

Label figures = loss-threshold frequency (MHz).The chart is a relative comparison at the same flux and threshold, not an application frequency limit — at operating flux below 50 mT the usable frequency is higher."≥" = the calculated threshold lies beyond the fitted range of that grade's loss model; the chart does not extrapolate, and the actual value may be higher."≈" = no 50 mT loss data; positioned by the band in the material table, with its capability compared by IDC.TM71's 0.39 is interpolated from two measured points at 300 and 500 kHz @50 mT.Only grades relevant to server power are shown.Bs at 1200 A/m; ★ = 2027 new material.

Typical values measured on toroidal cores; actual values vary with shape and size.Although ME03 belongs to the MnZn system, the catalogue also lists it in the EMI materials chapter of the NiZn volume.

TM59★ from the TAK 2027 MnZn catalog; other makers' values from their material data sheets.Bs measuring field: TAK 1200 A/m, DMEGC 1194 A/m, Proterial 1000 A/m, TDK 1200 A/m.The 500 kHz/100 mT/100 ℃ row is a tie.Third-party names are trademarks of their respective owners.

Data are typical values; μi and tanδ/μi measured at <0.2 mT, Bs at 3000 A/m.Other makers' corresponding grades: see "Grade cross-reference".

Cross-reference of power-material grades — major core manufacturers

Cross-reference of high-permeability grades — major core manufacturers

Competitor columns are initial screening candidates, not equivalents or drop-in replacements; verify with the same core, winding and operating conditions.

Other makers' grades are candidates for initial screening, not equivalents or drop-in replacements; verify on the same core, winding and operating conditions.A blank = no cross-reference data in this table, not that the maker has no such material.Third-party names are trademarks of their respective owners.

（ μi

Competitor columns are initial screening candidates, not equivalents or drop-in replacements; verify with the same core, winding and operating conditions.

μi and Bs are TAK typical values; for loss factors and their measuring frequencies see each material page.Other makers' grades are candidates for initial screening, not equivalents or drop-in replacements; verify on the same core, winding and operating conditions.A blank = no cross-reference data in this table, not that the maker has no such material.Third-party names are trademarks of their respective owners.