Fixed Inductors

Part Number	Description / PDF	Quantity
ETQ-P4M3R3KVK Panasonic	FIXED IND 3.3UH 8.9A 15.4 MOHM	0
ELJ-RF68NJF Panasonic	FIXED IND 68NH 120MA 4 OHM SMD	12548
ELJ-RF4N3ZFB Panasonic	FIXED IND 4.3NH 360MA 160 MOHM	19375
ELL-CTV471M Panasonic	FIXED IND 470UH 580MA 690 MOHM	1114
ETQ-P3MR33KVP Panasonic	FIXED IND 330NH 12.7A 5.3 MOHM	3912
ELL-CTV2R0N Panasonic	FIXED IND 2UH 6.3A 5.6 MOHM SMD	37
ELJ-NCR10KF Panasonic	FIXED IND 100NH 175MA 800 MOHM	10
ELJ-FBR27MF Panasonic	FIXED IND 270NH 650MA 320 MOHM	867
ELL-8TP2R5NB Panasonic	FIXED IND 2.5UH 6.5A 7 MOHM SMD	208
ELJ-NC82NKF Panasonic	FIXED IND 82NH 185MA 730 MOHM	4641
ELJ-PA1R5MF Panasonic	FIXED IND 1.5UH 550MA 180 MOHM	441
ELJ-FC680JF Panasonic	FIXED IND 68UH 70MA 16.6 OHM SMD	19
ELJ-QF20NJF Panasonic	FIXED IND 20NH 220MA 750 MOHM	65
ELJ-QF36NGF Panasonic	FIXED IND 36NH 160MA 1.6 OHM SMD	13024
ELL-6RH121M Panasonic	FIXED IND 120UH 280MA 1.5 OHM	16
ELL-5PM820M Panasonic	FIXED IND 82UH 320MA 780 MOHM	1897
ELJ-FC5R6JF Panasonic	FIXED IND 5.6UH 120MA 1.75 OHM	90
ELJ-RF56NJFB Panasonic	FIXED IND 56NH 130MA 2.5 OHM SMD	12224
ELC-18E470 Panasonic	FIXED IND 47UH 4.1A 30 MOHM TH	0
ETQ-P4LR56WFC Panasonic	FIXED IND 560NH 21A 1.56 MOHM	32

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