Fixed Inductors

Part Number	Description / PDF	Quantity
74477020 Würth Elektronik Midcom	FIXED IND 100UH 2.2A 220 MOHM	5643
7843320270 Würth Elektronik Midcom	FIXED IND 2.7UH 16.2A 4.7 MOHM	156
744307022 Würth Elektronik Midcom	FIXED IND 220NH 26A 0.29 MOHM	533
74437321033 Würth Elektronik Midcom	FIXED IND 3.3UH 2.3A 97 MOHM SMD	3901
74438356018 Würth Elektronik Midcom	FIXED IND 1.8UH 4.6A 30 MOHM SMD	3543
744104 Würth Elektronik Midcom	FIXED IND 167UH 1.35A 400 MOHM	0
7447860012 Würth Elektronik Midcom	FIXED IND 1.2NH 300MA 50 MOHM	3923
7443763540470 Würth Elektronik Midcom	FIXED IND 47UH 32A 6.38 MOHM TH	26
744776127 Würth Elektronik Midcom	FIXED IND 27UH 1.95A 110 MOHM	470
744761233A Würth Elektronik Midcom	FIXED IND 330NH 150MA 2 OHM SMD	1965
7440680047 Würth Elektronik Midcom	FIXED IND 4.7UH 1.85A 85 MOHM	0
7447471222 Würth Elektronik Midcom	FIXED IND 2.2MH 400MA 2.7 OHM TH	1
74438335022 Würth Elektronik Midcom	FIXED IND 2.2UH 1.8A 108 MOHM	1456
784383560068 Würth Elektronik Midcom	FIXED IND 680NH 8.2A 9 MOHM SMD	150
744045180 Würth Elektronik Midcom	FIXED IND 18UH 680MA 600 MOHM	960
7447471100 Würth Elektronik Midcom	FIXED IND 10UH 5.1A 22 MOHM TH	200
7447720471 Würth Elektronik Midcom	FIXED IND 470UH 660MA 970 MOHM	0
74404052068 Würth Elektronik Midcom	FIXED IND 6.8UH 1.9A 82.7 MOHM	2
7447786147 Würth Elektronik Midcom	FIXED IND 47UH 1.4A 298 MOHM SMD	1201
768772681 Würth Elektronik Midcom	FIXED IND 680UH 520MA 1.68 OHM	535

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