Fixed Inductors

Part Number	Description / PDF	Quantity
ELJ-QF4N3ZF Panasonic	FIXED IND 4.3NH 360MA 160 MOHM	18307
ELL-5GM270M Panasonic	FIXED IND 27UH 450MA 430 MOHM	1880
ELJ-RF6N8JF Panasonic	FIXED IND 6.8NH 320MA 300 MOHM	360
ELJ-PA560KF Panasonic	FIXED IND 56UH 110MA 3.3 OHM SMD	1214
ELC-18E271L Panasonic	FIXED IND 270UH 2A 83 MOHM TH	0
ELT-5KT330LB Panasonic	FIXED IND 33UH 360MA 1.2 OHM SMD	9934
ELL-6SH560M Panasonic	FIXED IND 56UH 550MA 290 MOHM	1129
ELJ-QF2N4DF Panasonic	FIXED IND 2.4NH 400MA 100 MOHM	13749
ELJ-QF3N0ZF Panasonic	FIXED IND 3NH 400MA 120 MOHM SMD	13842
ELC-18E821L Panasonic	FIXED IND 820UH 1.1A 210 MOHM TH	0
ELL-ATV681M Panasonic	FIXED IND 680UH 370MA 1.15 OHM	15249
ELJ-EA150KF Panasonic	FIXED IND 15UH 145MA 320 MOHM	2350
ETQ-P3M330KVN Panasonic	FIXED IND 33UH 2.1A 226.6 MOHM	0
ELL-6GG470M Panasonic	FIXED IND 47UH 480MA 610 MOHM	1
ELL-5PM120M Panasonic	FIXED IND 12UH 850MA 120 MOHM	595
ELJ-QE39NJFA Panasonic	FIXED IND 39NH 210MA 1 OHM SMD	272
ELJ-FBR47MF Panasonic	FIXED IND 470NH 580MA 400 MOHM	2470
ELJ-PE2N2KFA Panasonic	FIXED IND 2.2NH 2.1A 30 MOHM SMD	96
ETQ-P5M2R5YFC Panasonic	FIXED IND 2.5UH 18.1A 5.9 MOHM	0
ELT-5KT220LA Panasonic	FIXED IND 22UH 420MA 900 MOHM	3190

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