Fixed Inductors

Part Number	Description / PDF	Quantity
ELC-18E390L Panasonic	FIXED IND 39UH 4.5A 28 MOHM TH	0
ELC-18E181L Panasonic	FIXED IND 180UH 2.5A 67 MOHM TH	0
ELJ-FCR33MF Panasonic	FIXED IND 330NH 170MA 850 MOHM	20572
ELJ-RF39NJF Panasonic	FIXED IND 39NH 150MA 1.7 OHM SMD	506208
ETQ-P3M6R8KVN Panasonic	FIXED IND 6.8UH 4.5A 50.16 MOHM	5704
ETQ-P5M470YFC Panasonic	FIXED IND 47UH 4.2A 108.9 MOHM	385
ELL-6SH1R5M Panasonic	FIXED IND 1.5UH 3.2A 24 MOHM SMD	25
ELJ-QE3N3DFA Panasonic	FIXED IND 3.3NH 800MA 60 MOHM	2950
ELJ-QF1N3DF Panasonic	FIXED IND 1.3NH 400MA 70 MOHM	5600
ELL-4FG150MA Panasonic	FIXED IND 15UH 580MA 480 MOHM	0
ELC-18E472 Panasonic	FIXED IND 4.7MH 480MA 1.4 OHM TH	0
ELJ-QF30NJF Panasonic	FIXED IND 30NH 190MA 1.3 OHM SMD	12316
ELC-18E680L Panasonic	FIXED IND 68UH 3.6A 36 MOHM TH	0
ELJ-QF1N6DF Panasonic	FIXED IND 1.6NH 400MA 80 MOHM	19977
ETQ-P3H1R4BFA Panasonic	FIXED IND 1.43UH 12A 4.52 MOHM	14661
ETQ-PAF1R3EFA Panasonic	FIXED IND 1.3UH 17.7A 1.56 MOHM	2162
ELJ-QF27NJF Panasonic	FIXED IND 27NH 200MA 1.2 OHM SMD	16483
ETQ-P4M100KFM Panasonic	FIXED IND 10UH 6A 39.6MOHM SMD	473
ELC-18E180 Panasonic	FIXED IND 18UH 5.2A 19 MOHM TH	0
ELL-6GG680M Panasonic	FIXED IND 68UH 410MA 860 MOHM	1067

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