Fixed Inductors

Part Number	Description / PDF	Quantity
7440300068 Würth Elektronik Midcom	FIXED IND 680NH 1.3A 78 MOHM SMD	0
744710215 Würth Elektronik Midcom	FIXED IND 2UH 15A 1.7 MOHM TH	1888
74404086682 Würth Elektronik Midcom	FIXED IND 6.8MH 140MA 18.7 OHM	0
784776212 Würth Elektronik Midcom	FIXED IND 120UH 940MA 400 MOHM	0
744062120 Würth Elektronik Midcom	FIXED IND 12UH 1.43A 80 MOHM SMD	0
768772331 Würth Elektronik Midcom	FIXED IND 330UH 700MA 700 MOHM	109
784775112 Würth Elektronik Midcom	FIXED IND 12UH 2.18A 80 MOHM SMD	0
7447480152 Würth Elektronik Midcom	FIXED IND 1.5MH 680MA 1.8 OHM TH	139
744045003 Würth Elektronik Midcom	FIXED IND 3.3UH 1.4A 130 MOHM	145
7447054 Würth Elektronik Midcom	FIXED IND 10UH 2A 20 MOHM TH	155
74437368033 Würth Elektronik Midcom	FIXED IND 3.3UH 8A 11.8 MOHM SMD	2290
744776381 Würth Elektronik Midcom	FIXED IND 8MH 200MA 16 OHM SMD	435
7447452100 Würth Elektronik Midcom	FIXED IND 10UH 4.7A 20 MOHM TH	37
744306020 Würth Elektronik Midcom	FIXED IND 200NH 25A 0.26 MOHM	501
744778920W Würth Elektronik Midcom	FIXED IND 100UH 620MA 790 MOHM	0
7447471220 Würth Elektronik Midcom	FIXED IND 22UH 3.7A 48 MOHM TH	43
784771220 Würth Elektronik Midcom	FIXED IND 22UH 3.2A 40 MOHM SMD	251
744772560 Würth Elektronik Midcom	FIXED IND 56UH 2A 120 MOHM TH	7
7447649122 Würth Elektronik Midcom	FIXED IND 22UH 400MA 2.6 OHM SMD	1000
7447709152 Würth Elektronik Midcom	FIXED IND 1.5MH 650MA 2.3 OHM	9

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