Fixed Inductors

Part Number	Description / PDF	Quantity
7447709680 Würth Elektronik Midcom	FIXED IND 68UH 3.2A 89 MOHM SMD	0
744917039 Würth Elektronik Midcom	FIXED IND 3.9NH 1.6A 39 MOHM SMD	0
7447840068 Würth Elektronik Midcom	FIXED IND 6.8NH 300MA 290 MOHM	7597
744383660082 Würth Elektronik Midcom	FIXED IND 820NH 8.8A 9.6MOHM SMD	1785
7447840015 Würth Elektronik Midcom	FIXED IND 1.5NH 300MA 100 MOHM	9725
744786210A Würth Elektronik Midcom	FIXED IND 100NH 300MA 1.2 OHM	26211
7444013119150 Würth Elektronik Midcom	FIXED IND 15UH 11A 4.8MOHM TH	5
701014101 Würth Elektronik Midcom	FIXED IND 10UH 35A 1.1 MOHM SMD	0
744786018A Würth Elektronik Midcom	FIXED IND 1.8NH 600MA 100 MOHM	0
744765039A Würth Elektronik Midcom	FIXED IND 3.9NH 840MA 66 MOHM	6000
7447471331 Würth Elektronik Midcom	FIXED IND 330UH 1A 480 MOHM TH	116
74404043033A Würth Elektronik Midcom	FIXED IND 3.3UH 3.23A 33 MOHM	7010
744118 Würth Elektronik Midcom	FIXED IND 600UH 2.2A 330 MOHM TH	0
74435580680 Würth Elektronik Midcom	FIXED IND 6.8UH 28.5A 2.1 MOHM	1413
7447773100 Würth Elektronik Midcom	FIXED IND 10UH 2.6A 45 MOHM SMD	412
74404042022 Würth Elektronik Midcom	FIXED IND 2.2UH 2.2A 42 MOHM SMD	1814
7447745330 Würth Elektronik Midcom	FIXED IND 33UH 900MA 520 MOHM	100
7447713033 Würth Elektronik Midcom	FIXED IND 3.3UH 4.6A 24 MOHM SMD	70
74458010 Würth Elektronik Midcom	FIXED IND 10UH 4.3A 31 MOHM SMD	0
7447785004 Würth Elektronik Midcom	FIXED IND 4.7UH 2.65A 78 MOHM	2892

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