Fixed Inductors

Part Number	Description / PDF	Quantity
ELC-18E272L Panasonic	FIXED IND 2.7MH 650MA 890 MOHM	0
ELL-4GM270M Panasonic	FIXED IND 27UH 330MA 640 MOHM	1046
ELJ-QF8N2JF Panasonic	FIXED IND 8.2NH 320MA 350 MOHM	8480
ELJ-FC3R9KF Panasonic	FIXED IND 3.9UH 130MA 1.4 OHM	56
ETQ-P3M4R7KVP Panasonic	FIXED IND 4.7UH 4.1A 50.16 MOHM	1423
ELT-5KT101LB Panasonic	FIXED IND 100UH 190MA 4.3 OHM	12018
ELJ-PE3N3KF Panasonic	FIXED IND 3.3NH 2.1A 40 MOHM SMD	600
ELL-VGG120M Panasonic	FIXED IND 12UH 580MA 480 MOHM	1120
ELT-3KN118B Panasonic	FIXED IND 2.5MH 20MA 64 OHM SMD	4971
ELT-3KN121B Panasonic	FIXED IND 1MH 40MA 22.5 OHM SMD	2968
ETQ-P3M1R0YFN Panasonic	FIXED IND 1UH 10.7A 8.7 MOHM SMD	259
ELL-4GG8R2N Panasonic	FIXED IND 8.2UH 870MA 220 MOHM	118
ELC-18E330L Panasonic	FIXED IND 33UH 4.6A 26 MOHM TH	0
ELJ-QF12NJF Panasonic	FIXED IND 12NH 320MA 450 MOHM	10214
ELL-4GM470M Panasonic	FIXED IND 47UH 260MA 1.05 OHM	1954
ELL-6SH820M Panasonic	FIXED IND 82UH 450MA 600 MOHM	8
ELL-ATV102M Panasonic	FIXED IND 1MH 320MA 1.75 OHM SMD	380
ETQ-P6F3R4BFA Panasonic	FIXED IND 3.32UH 10A 6.48 MOHM	585
ELJ-RF56NGFB Panasonic	FIXED IND 56NH 130MA 2.5 OHM SMD	1768
ETQ-P1W3R3WFP Panasonic	FIXED IND 3.3UH 2.8A 103 MOHM	5977

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