Fixed Inductors

Part Number	Description / PDF	Quantity
74435586800 Würth Elektronik Midcom	FIXED IND 68UH 7.5A 27.3 MOHM	2240
7443310150 Würth Elektronik Midcom	FIXED IND 1.5UH 18.5A 3.5 MOHM	0
744052221 Würth Elektronik Midcom	FIXED IND 220UH 230MA 2.5 OHM	570
744901027 Würth Elektronik Midcom	FIXED IND 2.7NH 440MA 300 MOHM	8617
744383560047HT Würth Elektronik Midcom	FIXED IND 470NH 8.5A 8.1MOHM SMD	1457
744764012 Würth Elektronik Midcom	FIXED IND 1.2UH 390MA 750 MOHM	0
701014330 Würth Elektronik Midcom	FIXED IND 3.3UH 35A 1.1 MOHM SMD	50
744760239A Würth Elektronik Midcom	FIXED IND 390NH 210MA 2.2 OHM	0
74404052470 Würth Elektronik Midcom	FIXED IND 47UH 800MA 521 MOHM	4447
744787680 Würth Elektronik Midcom	FIXED IND 68UH 1.12A 290 MOHM	938
74431323016 Würth Elektronik Midcom	FIXED IND 160NH 26A 0.7 MOHM SMD	1188
74404054332 Würth Elektronik Midcom	FIXED IND 3.3MH 100MA 21.6 OHM	2514
74406043471 Würth Elektronik Midcom	FIXED IND 470UH 260MA 2.803 OHM	1883
74404043101A Würth Elektronik Midcom	FIXED IND 100UH 490MA 1.043 OHM	4393
74438334068 Würth Elektronik Midcom	FIXED IND 6.8UH 880MA 423.4 MOHM	388
744373560047 Würth Elektronik Midcom	FIXED IND 470NH 15.5A 3.33 MOHM	0
744765051A Würth Elektronik Midcom	FIXED IND 5.1NH 800MA 83 MOHM	1241
744373490068 Würth Elektronik Midcom	FIXED IND 680NH 12A 4.5 MOHM SMD	0
74437349100 Würth Elektronik Midcom	FIXED IND 10UH 3.2A 69 MOHM SMD	3902
74479876168 Würth Elektronik Midcom	FIXED IND 680NH 1.8A 60 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