Fixed Inductors

Part Number	Description / PDF	Quantity
744786215A Würth Elektronik Midcom	FIXED IND 150NH 200MA 1.6 OHM	5743
744787027 Würth Elektronik Midcom	FIXED IND 2.7UH 4.35A 17 MOHM	443
744762118A Würth Elektronik Midcom	FIXED IND 18NH 1A 100 MOHM SMD	1057
7440650022 Würth Elektronik Midcom	FIXED IND 2.2UH 6.2A 15 MOHM SMD	1016
7440430039 Würth Elektronik Midcom	FIXED IND 3.9UH 1.72A 60 MOHM	0
744761227C Würth Elektronik Midcom	FIXED IND 270NH 200MA 2.1 OHM	2515
744760218C Würth Elektronik Midcom	FIXED IND 180NH 400MA 960 MOHM	1779
74438333033 Würth Elektronik Midcom	FIXED IND 3.3UH 1.1A 266 MOHM	254
744052006 Würth Elektronik Midcom	FIXED IND 6.2UH 1.45A 80 MOHM	300
7447221103 Würth Elektronik Midcom	FIXED IND 10MH 230MA 9.7 OHM TH	233
744760027C Würth Elektronik Midcom	FIXED IND 2.7NH 800MA 80 MOHM	1924
7443341000 Würth Elektronik Midcom	FIXED IND 10UH 4.4A 41 MOHM SMD	579
78438323033 Würth Elektronik Midcom	FIXED IND 3.3UH 1.25A 264 MOHM	2647
78438335470 Würth Elektronik Midcom	FIXED IND 47UH 390MA 2.3 OHM SMD	812
744373580033 Würth Elektronik Midcom	FIXED IND 330NH 18.5A 2.15 MOHM	800
7447452392 Würth Elektronik Midcom	FIXED IND 3.9MH 280MA 4.8 OHM TH	25
7443550600 Würth Elektronik Midcom	FIXED IND 6UH 9.5A 13.5 MOHM SMD	265
74479876210C Würth Elektronik Midcom	FIXED IND 1UH 1.8A 75 MOHM SMD	65
7443557560 Würth Elektronik Midcom	FIXED IND 5.6UH 25A 2.82 MOHM	1241
7447720331 Würth Elektronik Midcom	FIXED IND 330UH 820MA 700 MOHM	121

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