Fixed Inductors

Part Number	Description / PDF	Quantity
ELL-SFG820MA Panasonic	FIXED IND 82UH 270MA 2 OHM SMD	5927
ELL-4GM180M Panasonic	FIXED IND 18UH 400MA 490 MOHM	1375
ELT-3KN124B Panasonic	FIXED IND 4MH 15MA 85 OHM SMD	8139
ELJ-QF3N0DF Panasonic	FIXED IND 3NH 400MA 120 MOHM SMD	15472
ETQ-P4LR24AFM Panasonic	FIXED IND 240NH 24A 1 MOHM SMD	3515
ETQ-P3WR82WFN Panasonic	FIXED IND 820NH 14A 8 MOHM SMD	2000
ELJ-PE5N6KFA Panasonic	FIXED IND 5.6NH 2.1A 55 MOHM SMD	69449
ELJ-FA1R5KF Panasonic	FIXED IND 1.5UH 210MA 750 MOHM	60
ELJ-QF5N1DF Panasonic	FIXED IND 5.1NH 350MA 180 MOHM	7830
ELC-18E271 Panasonic	FIXED IND 270UH 2A 83 MOHM TH	0
ELJ-PF2N7DF Panasonic	FIXED IND 2.7NH 1.8A 50 MOHM SMD	27624
ELJ-NCR27JF Panasonic	FIXED IND 270NH 140MA 1.25 OHM	1091
ELL-VFG220MC Panasonic	FIXED IND 22UH 430MA 710 MOHM	11
ELJ-LA680KF Panasonic	FIXED IND 68UH 145MA 5.5 OHM SMD	140
ELC-18E8R2L Panasonic	FIXED IND 8.2UH 6.2A 13 MOHM TH	0
ELJ-FCR82MF Panasonic	FIXED IND 820NH 130MA 1.4 OHM	10082
ELJ-RF6N8ZFB Panasonic	FIXED IND 6.8NH 320MA 300 MOHM	4681
ETQ-P4M4R7KFM Panasonic	FIXED IND 4.7UH 8.8A 18.48MOHM	1933
ELL-4FG100MA Panasonic	FIXED IND 10UH 750MA 290 MOHM	335
ELL-VFG150MC Panasonic	FIXED IND 15UH 480MA 540 MOHM	2245

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