Fixed Inductors

Part Number	Description / PDF	Quantity
74404064068 Würth Elektronik Midcom	FIXED IND 6.8UH 3A 31 MOHM SMD	1704
784778101 Würth Elektronik Midcom	FIXED IND 100UH 720MA 720 MOHM	0
7447412681 Würth Elektronik Midcom	FIXED IND 680UH 330MA 4 OHM TH	0
74438366015 Würth Elektronik Midcom	FIXED IND 1.5UH 6.7A 21.3 MOHM	1840
744762112A Würth Elektronik Midcom	FIXED IND 12NH 1A 80 MOHM SMD	0
7447714681 Würth Elektronik Midcom	FIXED IND 680UH 510MA 1.22 OHM	973
74437334068 Würth Elektronik Midcom	FIXED IND 6.8UH 2A 150 MOHM SMD	2824
744776360 Würth Elektronik Midcom	FIXED IND 6MH 230MA 14 OHM SMD	159
74438323047 Würth Elektronik Midcom	FIXED IND 4.7UH 940MA 388 MOHM	3164
744901082 Würth Elektronik Midcom	FIXED IND 8.2NH 220MA 1.1 OHM	0
744761087C Würth Elektronik Midcom	FIXED IND 8.7NH 700MA 100 MOHM	2950
744393440033 Würth Elektronik Midcom	FIXED IND 330NH 16.5A 2.1 MOHM	0
744761218C Würth Elektronik Midcom	FIXED IND 180NH 250MA 1 OHM SMD	540
744779100 Würth Elektronik Midcom	FIXED IND 10UH 1.85A 50 MOHM TH	75
74402900082 Würth Elektronik Midcom	FIXED IND 820NH 2.4A 45 MOHM SMD	0
744302015 Würth Elektronik Midcom	FIXED IND 150NH 30A 0.235 MOHM	947
74457182 Würth Elektronik Midcom	FIXED IND 82UH 2.2A 173 MOHM SMD	0
744042006 Würth Elektronik Midcom	FIXED IND 6.8UH 1.5A 100 MOHM	5520
7447221102 Würth Elektronik Midcom	FIXED IND 1MH 750MA 980 MOHM TH	0
74457118 Würth Elektronik Midcom	FIXED IND 18UH 4.6A 40 MOHM SMD	0

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