Fixed Inductors

Part Number	Description / PDF	Quantity
B78148E1332K000 TDK EPCOS	FIXED IND 3.3UH 3.05A 73 MOHM TH	727
B82442A1395K000 TDK EPCOS	FIXED IND 3.9MH 38MA 56 OHM SMD	0
B78148S1563J000 TDK EPCOS	FIXED IND 56UH 430MA 1.23 OHM TH	0
B82464A4485K000 TDK EPCOS	FIXED IND 4.8MH SMD	0
B82145A1474J000 TDK EPCOS	FIXED IND 470UH 510MA 1.9 OHM TH	1928
B82141A1333K000 TDK EPCOS	FIXED IND 33UH 300MA 1.12 OHM TH	7105
B82145A1154J000 TDK EPCOS	FIXED IND 150UH 770MA 900 MOHM	0
B82422A3101J100 TDK EPCOS	FIXED IND 100NH 440MA 260 MOHM	1258
B82475M1103M000 TDK EPCOS	FIXED IND 10UH 2.6A 60 MOHM SMD	0
B82442H1104J000 TDK EPCOS	FIXED IND 100UH 350MA 1.28 OHM	1637
B82476A1152M000 TDK EPCOS	FIXED IND 1.5UH 6.4A 9 MOHM SMD	0
B82496C3150J000 TDK EPCOS	FIXED IND 15NH 420MA 400 MOHM	9726
B82472P6473M000 TDK EPCOS	FIXED IND 47UH 1A 200 MOHM SMD	1488
B82498F3330J001 TDK EPCOS	FIXED IND 33NH 600MA 110 MOHM	0
B82496C3829Z000 TDK EPCOS	FIXED IND 8.2NH 650MA 180 MOHM	0
B82422T3680J000 TDK EPCOS	FIXED IND 68NH 450MA 230 MOHM	0
B82477D4682M000 TDK EPCOS	FIXED IND 6.8UH 4.15A 35 MOHM	0
B82498F3561G001 TDK EPCOS	FIXED IND 560NH 230MA 1.3 OHM	0
B82131A5301M000 TDK EPCOS	FIXED IND 40UH 300MA 4.1 OHM TH	0
B82141A1105K000 TDK EPCOS	FIXED IND 1MH 55MA 33 OHM TH	0

Fixed Inductors

1. Overview

Fixed inductors are passive electronic components designed to store energy in magnetic fields when electrical current flows through them. Unlike variable inductors, their inductance values remain constant during operation. These components play critical roles in filtering, signal processing, energy storage, and electromagnetic interference (EMI) suppression across modern electronics, including power supplies, communication systems, and automotive electronics.

2. Main Types and Functional Classification

Type	Functional Characteristics	Application Examples
Wirewound Inductors	High precision, high current handling, low resistance	Power supplies, DC-DC converters
Chip Inductors	Compact SMD package, stable performance at high frequencies	Mobile devices, RF circuits
Ferrite Bead Inductors	Effective high-frequency noise suppression	EMI filtering in digital circuits
Thin-Film Inductors	Ultra-compact, high Q-factor, tight tolerance	5G communication modules, IoT devices

3. Structure and Composition

Typical fixed inductors consist of:

Magnetic Core: Made from ferrite, powdered iron, or composite materials to concentrate magnetic flux
Coil Structure: Copper wire wound around the core (enamelled or silver-plated)
Encapsulation: Molded resin or ceramic coating for mechanical protection and insulation
Terminations: Solder-coated ends for PCB mounting (for SMD types) or leaded connections

4. Key Technical Specifications

Parameter	Description	Importance
Inductance (L)	Measured in henrys (H), determines energy storage capacity	Defines filtering/energy storage performance
Rated Current (I_rated)	Maximum DC current before saturation	Prevents core saturation and failure
DC Resistance (DCR)	Resistance of coil windings	Affects efficiency and thermal performance
Self-Resonant Frequency (SRF)	Frequency where inductor behaves as capacitor	Limits effective operating frequency range
Q Factor	Quality factor indicating efficiency	Higher Q = lower energy losses

5. Application Fields

Consumer Electronics: Smartphones, laptops, LED drivers
Industrial Equipment: Motor drives, power inverters
Automotive Systems: ECU modules, EV battery management
Telecom Infrastructure: Base station filters, optical transceivers

6. Leading Manufacturers and Products

Manufacturer	Representative Product	Key Features
Murata	LQH3NPN100M	10 H, 1.2A, 1.8 1.4mm chip inductor
TDK	MLZ2012A100T	100MHz SRF, 1.0 1.25mm for RF circuits
Vishay	IHLP2525CZER1R0M	1 H, 12A, composite construction
Coilcraft	0402DC-103J	10 H, 5% tolerance, ultra-low profile

7. Selection Guidelines

Key considerations during selection:

Calculate required inductance based on switching frequency and ripple current
Verify rated current exceeds maximum operating current by 20-30%
Select SRF higher than circuit operating frequency
Consider package size vs. thermal dissipation requirements
For EMI suppression: Choose ferrite beads with impedance curves matching target frequencies

8. Industry Trends

Current development trends include:

Miniaturization: Sub-0.5mm size inductors for wearable devices
High-Frequency Operation: Components supporting >10GHz 5G applications
Integrated Solutions: Combined inductor-filter modules
Material Innovation: Nanocrystalline cores for higher saturation flux
Automotive Focus: AEC-Q qualified parts for EV/HEV systems