Fixed Inductors

Part Number	Description / PDF	Quantity
7440680100 Würth Elektronik Midcom	FIXED IND 10UH 1.2A 200 MOHM SMD	0
74404031010A Würth Elektronik Midcom	FIXED IND 1UH 2.94A 31 MOHM SMD	100
74406042010 Würth Elektronik Midcom	FIXED IND 1UH 4.47A 23 MOHM SMD	1014
74408942470 Würth Elektronik Midcom	FIXED IND 47UH 660MA 608 MOHM	3090
701014100 Würth Elektronik Midcom	FIXED IND 1UH 50A 0.6 MOHM SMD	56
7843340100 Würth Elektronik Midcom	FIXED IND 1UH 12.8A 5.9MOHM SMD	174
74479887310A Würth Elektronik Midcom	FIXED IND 10UH 850MA 300 MOHM	12515
744373965015 Würth Elektronik Midcom	FIXED IND 1.5UH 18A 3 MOHM SMD	444
831754700 Würth Elektronik Midcom	FIXED IND 4.7UH 11A 12 MOHM SMD	0
7443310470 Würth Elektronik Midcom	FIXED IND 4.7UH 11.5A 11 MOHM	329
7447745033 Würth Elektronik Midcom	FIXED IND 3.3UH 3A 49 MOHM SMD	1561
744760212C Würth Elektronik Midcom	FIXED IND 120NH 400MA 510 MOHM	1233
74479773210 Würth Elektronik Midcom	FIXED IND 1UH 1.2A 180 MOHM SMD	669
831751001 Würth Elektronik Midcom	FIXED IND 10UH 7A 34 MOHM SMD	0
744750230030 Würth Elektronik Midcom	FIXED IND 3UH 7.6A 8.5 MOHM TH	2264
7443340680 Würth Elektronik Midcom	FIXED IND 6.8UH 5.5A 24 MOHM SMD	1245
74438335150 Würth Elektronik Midcom	FIXED IND 15UH 650MA 830 MOHM	2032
74402900033 Würth Elektronik Midcom	FIXED IND 330NH 3.1A 29 MOHM SMD	0
74404054015 Würth Elektronik Midcom	FIXED IND 1.5UH 4.3A 15 MOHM SMD	1318
744313180 Würth Elektronik Midcom	FIXED IND 1.8UH 14A 5.6 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