Fixed Inductors

Part Number	Description / PDF	Quantity
ELJ-QF1N8ZF Panasonic	FIXED IND 1.8NH 400MA 80 MOHM	6850
ELC-3GN470M Panasonic	FIXED IND 47UH 240MA 1.95 OHM	5650
ELL-SFG331MA Panasonic	FIXED IND 330UH 128MA 8.9 OHM	3668
ETQ-P2H2R6BFA Panasonic	FIXED IND 2.61UH 12A 4.98 MOHM	823
ETQ-P5M100YFC Panasonic	FIXED IND 10UH 8.5A 26.2 MOHM	0
ELL-6RH7R5M Panasonic	FIXED IND 7.5UH 1.25A 80 MOHM	0
ELJ-FC2R7KF Panasonic	FIXED IND 2.7UH 145MA 1.2 OHM	33
ELJ-QE4N7DFA Panasonic	FIXED IND 4.7NH 660MA 90 MOHM	598
ETQ-P3M2R2KVP Panasonic	FIXED IND 2.2UH 6.3A 22 MOHM SMD	16
ELL-ATV391M Panasonic	FIXED IND 390UH 520MA 690 MOHM	165
ELL-6RH680M Panasonic	FIXED IND 68UH 400MA 770 MOHM	11
ELJ-DA390JF Panasonic	FIXED IND 39UH 110MA 5.2 OHM SMD	3480
ELJ-NC10NKF Panasonic	FIXED IND 10NH 280MA 320 MOHM	946
ELJ-RF27NGFB Panasonic	FIXED IND 27NH 200MA 1.2 OHM SMD	8117
ELT-5KT680LA Panasonic	FIXED IND 68UH 260MA 2.6 OHM SMD	4923
ELJ-PE3N3KFA Panasonic	FIXED IND 3.3NH 2.1A 40 MOHM SMD	3901
ELJ-NC18NKF Panasonic	FIXED IND 18NH 250MA 400 MOHM	110
ELJ-QF1N1DF Panasonic	FIXED IND 1.1NH 400MA 60 MOHM	19050
ELJ-NCR18KF Panasonic	FIXED IND 180NH 155MA 1.05 OHM	17572
ELC-18E121 Panasonic	FIXED IND 120UH 2.8A 47 MOHM 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