Fixed Inductors

Part Number	Description / PDF	Quantity
74455222 Würth Elektronik Midcom	FIXED IND 220UH 200MA 3.11 OHM	760
7447211682 Würth Elektronik Midcom	FIXED IND 6.8MH 260MA 7.4 OHM TH	0
744786047A Würth Elektronik Midcom	FIXED IND 4.7NH 600MA 200 MOHM	1597
7443640470B Würth Elektronik Midcom	FIXED IND 4.7UH 47.5A 0.968 MOHM	0
784774022 Würth Elektronik Midcom	FIXED IND 2.2UH 4.6A 41 MOHM SMD	0
7447231682 Würth Elektronik Midcom	FIXED IND 6.8MH 300MA 5.75 OHM	159
74404054221 Würth Elektronik Midcom	FIXED IND 220UH 500MA 1.4OHM SMD	0
744029002 Würth Elektronik Midcom	FIXED IND 2.2UH 1.5A 105 MOHM	9545
74438335470 Würth Elektronik Midcom	FIXED IND 47UH 390MA 2.3 OHM SMD	1679
744731471 Würth Elektronik Midcom	FIXED IND 470UH 600MA 1.3 OHM TH	148
74404300033 Würth Elektronik Midcom	FIXED IND 330NH 4A 12 MOHM SMD	352
7447471068 Würth Elektronik Midcom	FIXED IND 6.8UH 6.4A 13.9 MOHM	76
744311047 Würth Elektronik Midcom	FIXED IND 400NH 19A 1.85 MOHM	2414
74404064047 Würth Elektronik Midcom	FIXED IND 4.7UH 3.3A 26 MOHM SMD	834
744761047C Würth Elektronik Midcom	FIXED IND 4.7NH 700MA 80 MOHM	0
74404054222 Würth Elektronik Midcom	FIXED IND 2.2MH 140MA 12.9 OHM	296
7443640150B Würth Elektronik Midcom	FIXED IND 1.5UH 56A 0.484 MOHM	130
744308040 Würth Elektronik Midcom	FIXED IND 400NH 25A 0.37 MOHM	1114
744917130 Würth Elektronik Midcom	FIXED IND 30NH 920MA 160 MOHM	0
784778220 Würth Elektronik Midcom	FIXED IND 22UH 1.55A 187 MOHM	974

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