Fixed Inductors

Part Number	Description / PDF	Quantity
ELJ-FCR27KF Panasonic	FIXED IND 270NH 180MA 750 MOHM	6368
ELL-4LG2R2NA Panasonic	FIXED IND 2.2UH 1.7A 55 MOHM SMD	319
ELC-3FN1R0N Panasonic	FIXED IND 1UH 1.4A 80 MOHM SMD	4501
ELJ-ND33NKF Panasonic	FIXED IND 33NH 395MA 390 MOHM	1
ELL-8TP6R8NB Panasonic	FIXED IND 6.8UH 3.5A 18 MOHM SMD	1018
ETQ-P4M4R7KFN Panasonic	FIXED IND 4.7UH 7.3A 22.77MOHM	343
ELJ-QF1N8DF Panasonic	FIXED IND 1.8NH 400MA 80 MOHM	13873
ELL-8UV390M Panasonic	FIXED IND 39UH 1.5MA 90 OHM SMD	988
ELC-3GN680M Panasonic	FIXED IND 68UH 190MA 3 OHM SMD	1555
ELL-4LG151MA Panasonic	FIXED IND 150UH 220MA 3 OHM SMD	955
ELJ-PB180KF Panasonic	FIXED IND 18UH 310MA 900 MOHM	2
ETQ-P3MR68KVP Panasonic	FIXED IND 680NH 10.2A 8.36 MOHM	10
ELL-8UV680M Panasonic	FIXED IND 68UH 1.1MA 130 OHM SMD	239
ELC-3GN6R8N Panasonic	FIXED IND 6.8UH 680MA 250 MOHM	4405
ETQ-P6F0R6BFA Panasonic	FIXED IND 580NH 19A 1.44 MOHM	172
ELT-5KT680LB Panasonic	FIXED IND 68UH 260MA 2.6 OHM SMD	4903
ETQ-P5M6R8YFM Panasonic	FIXED IND 6.8UH 6.9A 29.4 MOHM	615
ELC-18E182L Panasonic	FIXED IND 1.8MH 800MA 570 MOHM	0
ELC-18E152L Panasonic	FIXED IND 1.5MH 900MA 510 MOHM	0
ETQ-P8M4R7JFA Panasonic	FIXED IND 4.7UH 16.8A 5.39 MOHM	24

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