MnZn Power Ferrite · High-frequency power · Material specification

TM65★ 2027 NEW

HIGH-FREQUENCY INDUCTOR POWER FERRITE

VRM / TLVR InductorPOL High-Frequency InductorMHz DC-DC InductorHigh-Frequency Transformer

TM65 is a high-frequency inductor MnZn power ferrite with an initial permeability (μi) of 1300, the highest of the high-frequency power grades, a saturation flux density (Bs) of 540 mT at 25 °C (440 mT at 100 °C) and a Curie temperature above 240 °C. Its loss minimum lies at operating temperature: Pcv at 1 MHz / 50 mT decreases from 250 kW/m³ at 25 °C to 180 kW/m³ at 100 °C, at 800 kHz / 60 mT it is 300 → 220 kW/m³ and at 1 MHz / 30 mT 70 → 50 kW/m³; the remanence (Br) at 100 °C is 50 mT. In the DC-bias measurement of eight grades on the same UD core, its 100 °C I@90 % reaches 47.3 A in the 220 nH band, equivalent to TM59 with lower high-frequency loss, meeting the requirements of single-turn high-current MHz-class inductors. Typical applications are VRM and TLVR inductors for CPU/GPU power, POL high-frequency inductors, and 1 MHz-class DC-DC inductors and transformers. Among the high-frequency grades TM65 is the recommended inductor grade for new designs (TM61 is the earlier generation, retained for existing designs and still applicable to 1–3 MHz transformers); small-size MHz transformers should use TM63. At 500 kHz / 100 mT it reads 600 → 630 kW/m³, so large-flux transformers below 700 kHz remain the domain of TM59.

Magnetic Characteristics

Characteristic	Condition	25 ℃	100 ℃	Unit
Initial Permeability μiInitial Permeability μi	100 kHz & <0.2 mT	1300±25%	—	—
Amplitude Permeability μaAmplitude Permeability μa	25 kHz/400 mT	> 2400	> 2400	—
Saturation Flux Density BsSaturation Flux Density Bs	1200 A/m 100 Hz	540	440	mT
Remanence BrRemanence Br	1200 A/m 100 Hz	70	50	mT
Coercivity HcCoercivity Hc	1200 A/m 100 Hz	15	20	A/m
Loss FactorLoss Factor	100 kHz & <0.2 mT	<15	—	10⁻⁶
Curie Temperature TcCurie Temperature Tc	100 kHz & <0.2 mT	>240	—	℃
Density DDensity D	Archimedes method	>4.85	—	g/cm³
Electrical Resistivity ρElectrical Resistivity ρ	DC Current	>10	—	Ω·m

Power Loss · kW/m³

Condition	25 ℃	100 ℃	Condition	25 ℃	100 ℃
500 kHz/50 mT	70	50	800 kHz/80 mT	650	600
500 kHz/100 mT	600	630	1 MHz/30 mT	70	50
800 kHz/60 mT	300	220	1 MHz/50 mT	250	180

Pcv = K·f^α·B^β

Range	K	α	β
100 ≤500	5.064E-09	1.3197	3.7683
100 ≤1000	1.313E-10	1.7771	3.9893
100 ≤3000	2.212E-13	2.7658	3.8768

Characteristic curves

CURVE 01

CURVE 02

CURVE 03

CURVE 04

CURVE 05

CURVE 06

Applications

Application	Role	Band	Temperature
Flyback transformer (>150 W)	Alternative	0.7–1 MHz	40–80 ℃
Flyback transformer (≤150 W, by IDC)	First choice	0.8–3 MHz	—
LLC / resonant & bridge transformer (incl. Lr)	Alternative	0.7–1 MHz	40–80 ℃
Small-size MHz transformer (1–5 MHz)	Alternative	1–3 MHz	40–80 ℃
Buck output inductor	First choice	0.8–3 MHz	—
Boost input inductor	First choice	0.8–3 MHz	—
PFC chokes & high-current storage inductors	First choice	0.8–3 MHz	—
Forward / push-pull output inductor	First choice	0.8–3 MHz	—
VRM / TLVR / PoL inductor	First choice	0.8–1 MHz	—
Wideband signal transformer / balun	Alternative	1–3 MHz	—

Used in circuits

First choiceBuck converter — output inductor · Buck 0.8–3 MHz First choiceBuck converter — output inductor · VRM／TLVR 0.8–1 MHz First choiceBoost converter — input inductor · 0.8–3 MHz First choiceBoost PFC — PFC choke · 0.8–3 MHz First choiceFlyback converter — energy-storage transformer · ≦150 W 0.8–3 MHz AlternativeFlyback converter — energy-storage transformer · >150 W 0.3–1 MHz First choiceForward converter — transformer & output inductor · Output inductor 0.8–3 MHz First choicePush-pull converter — centre-tapped transformer · Output inductor 0.8–3 MHz AlternativeHalf-bridge LLC — transformer & resonant inductor · 0.3–1 MHz AlternativeSignal transformers — wideband, balun, current transformer · 1–5 MHz (signal)