Fixed Inductors

Part Number	Description / PDF	Quantity
ELL-6UH180M Panasonic	FIXED IND 18UH 1.4A 88 MOHM SMD	280
ELJ-QF2N7ZF Panasonic	FIXED IND 2.7NH 400MA 100 MOHM	19855
ELJ-FCR56KF Panasonic	FIXED IND 560NH 150MA 1.1 OHM	94
ETQ-P4LR36WFC Panasonic	FIXED IND 360NH 24A 1.1 MOHM SMD	0
ELL-4FG1R0NA Panasonic	FIXED IND 1UH 1.95A 45 MOHM SMD	1987
ELJ-QF20NGF Panasonic	FIXED IND 20NH 220MA 750 MOHM	9442
ETQ-P4M220KVK Panasonic	FIXED IND 22UH 3.8A 83.93 MOHM	213
ELJ-PF4N7DFB Panasonic	FIXED IND 4.7NH 1.3A 100 MOHM	9035
ELJ-NC68NJF Panasonic	FIXED IND 68NH 190MA 680 MOHM	11139
ELJ-QE33NJFA Panasonic	FIXED IND 33NH 230MA 820 MOHM	5502
ELL-5PM560M Panasonic	FIXED IND 56UH 400MA 610 MOHM	684
ETQ-P3W1R5WFN Panasonic	FIXED IND 1.5UH 11A 13 MOHM SMD	3441
ETQ-P4M4R7KVK Panasonic	FIXED IND 4.7UH 8.3A 17.71 MOHM	8
ELC-18E681 Panasonic	FIXED IND 680UH 1.2A 190 MOHM TH	0
ELL-4GG1R2N Panasonic	FIXED IND 1.2UH 1.9A 50 MOHM SMD	737
ELJ-FB8R2KF Panasonic	FIXED IND 8.2UH 250MA 1.6 OHM	781
ELJ-QF1N3ZF Panasonic	FIXED IND 1.3NH 400MA 70 MOHM	17589
ELL-6PG5R6N Panasonic	FIXED IND 5.6UH 1.65A 65 MOHM	99223
ELJ-QF6N2ZF Panasonic	FIXED IND 6.2NH 330MA 250 MOHM	17548
ETQ-P4M220KVC Panasonic	FIXED IND 22UH 5A 66 MOHM SMD	13

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