Fixed Inductors

Part Number	Description / PDF	Quantity
ETQ-P4M150KVK Panasonic	FIXED IND 15UH 4.5A 60.5 MOHM	0
ETQ-P5M101YGM Panasonic	FIXED IND 95UH 1.9A 382.8 MOHM	450
ELL-4LG220MA Panasonic	FIXED IND 22UH 640MA 390 MOHM	9450
ELJ-FC180KF Panasonic	FIXED IND 18UH 65MA 5.4 OHM SMD	13
ETQ-P6F2R9LFA Panasonic	FIXED IND 2.9UH 9.3A 6.48 MOHM	6
ELC-3GN150M Panasonic	FIXED IND 15UH 430MA 600 MOHM	1408
ETQ-P4M470KVC Panasonic	FIXED IND 47UH 3.4A 145.2 MOHM	0
ELC-18E150L Panasonic	FIXED IND 15UH 5.4A 17 MOHM TH	0
ELC-18E220L Panasonic	FIXED IND 22UH 5A 22 MOHM TH	0
ELL-6PG101M Panasonic	FIXED IND 100UH 400MA 1 OHM SMD	0
ELL-CTV120M Panasonic	FIXED IND 12UH 3.7A 22 MOHM SMD	0
ELC-18E561 Panasonic	FIXED IND 560UH 1.4A 170 MOHM TH	0
ELC-18E822 Panasonic	FIXED IND 8.2MH 350MA 2.4 OHM TH	0
ELL-6UH821M Panasonic	FIXED IND 820UH 200MA 3.14 OHM	542
ELC-18E120L Panasonic	FIXED IND 12UH 5.6A 16 MOHM TH	0
ELJ-SC820KF Panasonic	FIXED IND 82UH 14MA 7.4 OHM SMD	214
ELL-6PG680M Panasonic	FIXED IND 68UH 500MA 700 MOHM	355
ELJ-FAR33KF2 Panasonic	FIXED IND 330NH 330MA 350 MOHM	1404
ETQ-P3M1R0KVN Panasonic	FIXED IND 1UH 12.1A 6.82 MOHM	0
ETQ-P3WR68WFN Panasonic	FIXED IND 680NH 17A 5.5 MOHM SMD	1821

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