Fixed Inductors

Part Number	Description / PDF	Quantity
ELG-TEA2R2NA Panasonic	FIXED IND 2.2UH 800MA 200 MOHM	4000
ETQ-P4M3R3KFN Panasonic	FIXED IND 3.3UH 9.2A 14.41MOHM	104
ELL-8TP681MB Panasonic	FIXED IND 680UH 430MA 1.3 OHM	333
ELL-VFG1R5NC Panasonic	FIXED IND 1.5UH 1.55A 61 MOHM	2962
ELJ-RF7N5ZFB Panasonic	FIXED IND 7.5NH 320MA 330 MOHM	5115
ETQ-P3H0R4BFA Panasonic	FIXED IND 360NH 23A 1.04 MOHM	29
ELJ-QF7N5ZF Panasonic	FIXED IND 7.5NH 320MA 330 MOHM	5264
ELJ-NCR12JF Panasonic	FIXED IND 120NH 170MA 870 MOHM	2
ELJ-QE10NJFA Panasonic	FIXED IND 10NH 450MA 210 MOHM	7298
ETQ-P6M3R3YLC Panasonic	FIXED IND 3.3UH 17A 6.6 MOHM SMD	250
ELJ-RF1N2ZFB Panasonic	FIXED IND 1.2NH 400MA 60 MOHM	10829
ELL-SFG181MA Panasonic	FIXED IND 180UH 180MA 4.3 OHM	3946
ELJ-FC180JF Panasonic	FIXED IND 18UH 65MA 5.4 OHM SMD	13
ELJ-RF1N5ZFB Panasonic	FIXED IND 1.5NH 400MA 70 MOHM	16532
ELT-3KN131B Panasonic	FIXED IND 2MH 20MA 44 OHM SMD	0
ELL-5PM220M Panasonic	FIXED IND 22UH 680MA 210 MOHM	349
ELL-5GM150M Panasonic	FIXED IND 15UH 650MA 250 MOHM	1994
ELJ-QF5N1ZF Panasonic	FIXED IND 5.1NH 350MA 180 MOHM	3339
ELL-6PM7R5N Panasonic	FIXED IND 7.5UH 1.3A 70 MOHM SMD	432
ELJ-RF4N3DFB Panasonic	FIXED IND 4.3NH 360MA 160 MOHM	20000

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