Fixed Inductors

Part Number	Description / PDF	Quantity
ELJ-RE1N8DFA Panasonic	FIXED IND 1.8NH 500MA 80 MOHM	764
ELJ-NA3R3JF Panasonic	FIXED IND 3.3UH 100MA 4.2 OHM	73
ELL-ATV821M Panasonic	FIXED IND 820UH 340MA 1.27 OHM	1225
ETQ-P5M220YFK Panasonic	FIXED IND 22UH 4.8A 70 MOHM SMD	0
ELJ-QE22NGFA Panasonic	FIXED IND 22NH 290MA 520 MOHM	2091
ELC-18E100L Panasonic	FIXED IND 10UH 5.9A 14 MOHM TH	0
ELL-ATV330M Panasonic	FIXED IND 33UH 1.8A 62 MOHM SMD	5639
ELC-18E820 Panasonic	FIXED IND 82UH 3.5A 40 MOHM TH	0
ELC-18E151L Panasonic	FIXED IND 150UH 2.6A 61 MOHM TH	0
ETQ-P4LR68XFC Panasonic	FIXED IND 680NH 21A 1.58 MOHM	2000
ELL-6SH271M Panasonic	FIXED IND 270UH 260MA 2.4 OHM	524
ELL-SFG560MA Panasonic	FIXED IND 56UH 330MA 1.3 OHM SMD	3964
ELL-SFG680MA Panasonic	FIXED IND 68UH 310MA 1.5 OHM SMD	3750
ELC-3FN220M Panasonic	FIXED IND 22UH 330MA 1.18 OHM	5746
ELC-3GN8R2N Panasonic	FIXED IND 8.2UH 540MA 410 MOHM	2452
ELL-VEG220M Panasonic	FIXED IND 22UH 400MA 1.2 OHM SMD	2479
ETQ-P6M2R5YLC Panasonic	FIXED IND 2.5UH 19.6A 5 MOHM SMD	150
ELL-4GG4R7N Panasonic	FIXED IND 4.7UH 1A 160 MOHM SMD	1800
ETQ-P4M2R2YFN Panasonic	FIXED IND 2.2UH 10.2A 11.44 MOHM	728
ELL-CTV181M Panasonic	FIXED IND 180UH 930MA 270 MOHM	255

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