Fixed Inductors

Part Number	Description / PDF	Quantity
ELJ-FAR27KF2 Panasonic	FIXED IND 270NH 345MA 320 MOHM	5101
ETQ-P5MR68YLC Panasonic	FIXED IND 680NH 31.5A 1.93 MOHM	316
ELJ-RF68NJFB Panasonic	FIXED IND 68NH 120MA 4 OHM SMD	26865
ETQ-P3M220HFN Panasonic	FIXED IND 22UH 2.5A 158.4 MOHM	3495
ELL-SFG121MA Panasonic	FIXED IND 120UH 210MA 3.1 OHM	3978
ELL-4GM2R4N Panasonic	FIXED IND 2.4UH 1.15A 66 MOHM	217
ELJ-NDR18JF Panasonic	FIXED IND 180NH 195MA 1.61 OHM	12878
ETQ-P6F4R1LFA Panasonic	FIXED IND 4.1UH 7.9A 8.64 MOHM	7736
ELJ-RF56NJF Panasonic	FIXED IND 56NH 130MA 2.5 OHM SMD	3741
ETQ-P1H1R0BFA Panasonic	FIXED IND 1UH 19A 1.56 MOHM SMD	167
ETQ-P4M220KFM Panasonic	FIXED IND 22UH 3.9A 92.51 MOHM	180
ELJ-RF3N3ZFB Panasonic	FIXED IND 3.3NH 400MA 120 MOHM	613
ELJ-LA6R8KF Panasonic	FIXED IND 6.8UH 460MA 550 MOHM	1580
ETQ-P4LR45XFC Panasonic	FIXED IND 470NH 25A 1.1 MOHM SMD	1998
ETQ-P5M4R7YFM Panasonic	FIXED IND 4.7UH 8A 23 MOHM SMD	824
ETQ-P4M100KVC Panasonic	FIXED IND 10UH 7.6A 27.94 MOHM	0
ELT-5KN134C Panasonic	FIXED IND 1MH 55MA 11.5 OHM SMD	0
ELJ-PF3N3DFB Panasonic	FIXED IND 3.3NH 1.5A 70 MOHM SMD	12163
ETQ-P4LR36AFM Panasonic	FIXED IND 360NH 20A 1.35 MOHM	2975
ELJ-FB471JF Panasonic	FIXED IND 470UH 55MA 31 OHM SMD	35

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