Fixed Inductors

Part Number	Description / PDF	Quantity
ELJ-QF3N3DF Panasonic	FIXED IND 3.3NH 400MA 120 MOHM	5268
ELJ-QF13NJF Panasonic	FIXED IND 13NH 280MA 530 MOHM	17252
ETQ-P4M330KVC Panasonic	FIXED IND 33UH 4.2A 93.06 MOHM	196
ETQ-P4M2R2KVK Panasonic	FIXED IND 2.2UH 11.4A 9.35 MOHM	41
ELJ-QF1N5DF Panasonic	FIXED IND 1.5NH 400MA 70 MOHM	9910
ETQ-P4M4R7YFP Panasonic	FIXED IND 4.7UH 4.8A 39.6 MOHM	44
ELC-18E331L Panasonic	FIXED IND 330UH 1.9A 110 MOHM TH	0
ELC-18E100 Panasonic	FIXED IND 10UH 5.9A 14 MOHM TH	0
ELT-3KN128B Panasonic	FIXED IND 560UH 45MA 15 OHM SMD	0
ELC-18E182 Panasonic	FIXED IND 1.8MH 800MA 570 MOHM	0
ETQ-P4M330YFN Panasonic	FIXED IND 33UH 2.5A 189.2 MOHM	680
ETQ-P5M101YGK Panasonic	FIXED IND 100UH 2.1A 333 MOHM	0
ELC-18E270L Panasonic	FIXED IND 27UH 4.8A 23 MOHM TH	0
ETQ-P3M220KVN Panasonic	FIXED IND 22UH 2.7A 140.8 MOHM	0
ELC-18E391 Panasonic	FIXED IND 390UH 1.8A 120 MOHM TH	0
ELJ-LC4R7MF Panasonic	FIXED IND 4.7UH 350MA 750 MOHM	1935
ELJ-FB120JF Panasonic	FIXED IND 12UH 225MA 1.9 OHM SMD	110
ELC-18E330 Panasonic	FIXED IND 33UH 4.6A 26 MOHM TH	0
ELL-4GG100M Panasonic	FIXED IND 10UH 770MA 250 MOHM	3518
ELL-6GG150M Panasonic	FIXED IND 15UH 900MA 210 MOHM	275

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