Fixed Inductors

Part Number	Description / PDF	Quantity
ELJ-QF1N2ZF Panasonic	FIXED IND 1.2NH 400MA 60 MOHM	18725
ELJ-QF1N0DF Panasonic	FIXED IND 1NH 400MA 50 MOHM SMD	5356
ELL-8UV150M Panasonic	FIXED IND 15UH 2.5MA 26 OHM SMD	729
ELJ-NCR18JF Panasonic	FIXED IND 180NH 155MA 1.05 OHM	89
ELJ-FA820JF Panasonic	FIXED IND 82UH 60MA 10 OHM SMD	1058
ELJ-FB181JF Panasonic	FIXED IND 180UH 85MA 13 OHM SMD	120228
ELJ-RF43NGFB Panasonic	FIXED IND 43NH 150MA 1.9 OHM SMD	5160
ELC-3GN4R7N Panasonic	FIXED IND 4.7UH 760MA 200 MOHM	3870
ELT-5KT4R7MB Panasonic	FIXED IND 4.7UH 950MA 200 MOHM	6244
ELJ-QF33NGF Panasonic	FIXED IND 33NH 170MA 1.4 OHM SMD	28194
ELJ-QF2N0ZF Panasonic	FIXED IND 2NH 400MA 90 MOHM SMD	26463
ELC-18E180L Panasonic	FIXED IND 18UH 5.2A 19 MOHM TH	0
ETQ-P3M3R3KVN Panasonic	FIXED IND 3.3UH 6.1A 26.51 MOHM	0
ETQ-P5M330YFC Panasonic	FIXED IND 33UH 5A 75.4 MOHM SMD	77
ELJ-RF33NJF Panasonic	FIXED IND 33NH 170MA 1.4 OHM SMD	3334
ETQ-P4M1R0KVK Panasonic	FIXED IND 1UH 17.3A 4.07 MOHM	244
ELL-8TP4R7NB Panasonic	FIXED IND 4.7UH 4A 14 MOHM SMD	0
ELT-3KN162B Panasonic	FIXED IND 4MH 15MA 117 OHM SMD	732
ELJ-PF4N7DF Panasonic	FIXED IND 4.7NH 1.3A 100 MOHM	16022
ELL-VEG3R3N Panasonic	FIXED IND 3.3UH 820MA 210 MOHM	1092

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