Fixed Inductors

Part Number	Description / PDF	Quantity
ELC-18E560L Panasonic	FIXED IND 56UH 3.8A 31 MOHM TH	0
ETQ-P4M470KFM Panasonic	FIXED IND 47UH 2.9A 163.46MOHM	0
ELJ-NCR56JF Panasonic	FIXED IND 560NH 120MA 1.7 OHM	338
ELJ-NA68NMF Panasonic	FIXED IND 68NH 400MA 250 MOHM	20608
ELL-6GG330M Panasonic	FIXED IND 33UH 580MA 510 MOHM	2626
ELC-3FN5R6N Panasonic	FIXED IND 5.6UH 680MA 310 MOHM	2350
ETQ-P3W4R7WFN Panasonic	FIXED IND 4.7UH 5.7A 40.3 MOHM	0
ETQ-P5M3R3YFC Panasonic	FIXED IND 3.3UH 15.7A 7.9 MOHM	1226
ELL-6RH330M Panasonic	FIXED IND 33UH 600MA 380 MOHM	597
ELJ-QF11NJF Panasonic	FIXED IND 11NH 320MA 430 MOHM	8621
ELC-18E121L Panasonic	FIXED IND 120UH 2.8A 47 MOHM TH	0
ELJ-QF22NGF Panasonic	FIXED IND 22NH 200MA 800 MOHM	26
ELC-18E390 Panasonic	FIXED IND 39UH 4.5A 28 MOHM TH	0
ETQ-P5M3R3YFK Panasonic	FIXED IND 3.3UH 12.5A 10.45 MOHM	970
ELL-6PV5R6N Panasonic	FIXED IND 5.6UH 1.45A 49 MOHM	574
ELJ-QF18NGF Panasonic	FIXED IND 18NH 240MA 700 MOHM	11083
ELC-3FN1R8N Panasonic	FIXED IND 1.8UH 1.1A 110 MOHM	722
ELJ-QE5N6ZFA Panasonic	FIXED IND 5.6NH 600MA 110 MOHM	22
ELJ-QF39NJF Panasonic	FIXED IND 39NH 150MA 1.7 OHM SMD	1198
ELJ-FA8R2KF Panasonic	FIXED IND 8.2UH 140MA 2 OHM SMD	1772

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