Fixed Inductors

Part Number	Description / PDF	Quantity
784778470 Würth Elektronik Midcom	FIXED IND 47UH 1.1A 348 MOHM SMD	3596
744765175GA Würth Elektronik Midcom	FIXED IND 75NH 160MA 1.2OHM SMD	2940
744776182 Würth Elektronik Midcom	FIXED IND 82UH 1.11A 250 MOHM	0
74438356015HT Würth Elektronik Midcom	FIXED IND 1.5UH 5.5A 20.7 MOHM	1870
7447797110 Würth Elektronik Midcom	FIXED IND 1.1UH 11.2A 6.65 MOHM	491
7447860168 Würth Elektronik Midcom	FIXED IND 68NH 300MA 850 MOHM	3785
7447840127 Würth Elektronik Midcom	FIXED IND 27NH 300MA 670 MOHM	7320
744764118 Würth Elektronik Midcom	FIXED IND 18UH 120MA 3.3 OHM SMD	1000
744766012 Würth Elektronik Midcom	FIXED IND 1.2UH 430MA 550 MOHM	0
744066005 Würth Elektronik Midcom	FIXED IND 5UH 4.9A 22 MOHM SMD	0
744774118 Würth Elektronik Midcom	FIXED IND 18UH 1.45A 150 MOHM	1145
744303012 Würth Elektronik Midcom	FIXED IND 120NH 31A 0.325 MOHM	95
744043101 Würth Elektronik Midcom	FIXED IND 100UH 510MA 600 MOHM	919
74455168 Würth Elektronik Midcom	FIXED IND 68UH 400MA 860 MOHM	0
744043151 Würth Elektronik Midcom	FIXED IND 150UH 420MA 860 MOHM	1011
7447714150 Würth Elektronik Midcom	FIXED IND 15UH 3.5A 43 MOHM SMD	1538
74456233 Würth Elektronik Midcom	FIXED IND 330UH 700MA 1.15 OHM	870
744325040 Würth Elektronik Midcom	FIXED IND 400NH 24A 0.67 MOHM	0
744787181 Würth Elektronik Midcom	FIXED IND 180UH 680MA 794 MOHM	350
7447820010 Würth Elektronik Midcom	FIXED IND 1NH 470MA 110 MOHM SMD	14990

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