Fixed Inductors

Part Number	Description / PDF	Quantity
744777928 Würth Elektronik Midcom	FIXED IND 820UH 210MA 5.2 OHM	0
744911088 Würth Elektronik Midcom	FIXED IND 8.8NH 1.6A 12 MOHM SMD	0
744040640047 Würth Elektronik Midcom	FIXED IND 470NH 6.85A 6 MOHM SMD	1496
7447745047 Würth Elektronik Midcom	FIXED IND 4.7UH 2.5A 65 MOHM SMD	3807
744040520047 Würth Elektronik Midcom	FIXED IND 470NH 4.9A 13.9 MOHM	121
7440320015 Würth Elektronik Midcom	FIXED IND 1.5UH 660MA 130 MOHM	0
74404043151A Würth Elektronik Midcom	FIXED IND 150UH 390MA 1.634 OHM	824
74437324150 Würth Elektronik Midcom	FIXED IND 15UH 1.2A 374 MOHM SMD	5108
744731822 Würth Elektronik Midcom	FIXED IND 8.2MH 100MA 16 OHM TH	110
7447798910 Würth Elektronik Midcom	FIXED IND 9.1UH 7.35A 14.35 MOHM	797
744911098 Würth Elektronik Midcom	FIXED IND 9.85NH 1.6A 13 MOHM	0
7447715180 Würth Elektronik Midcom	FIXED IND 18UH 3.2A 51 MOHM SMD	568
74437377033 Würth Elektronik Midcom	FIXED IND 3.3UH 9.5A 11 MOHM SMD	113
7447798131 Würth Elektronik Midcom	FIXED IND 13UH 5.85A 22.5 MOHM	336
74406900052 Würth Elektronik Midcom	FIXED IND 520NH 4.3A 20 MOHM SMD	0
7447820122 Würth Elektronik Midcom	FIXED IND 22NH 150MA 1 OHM SMD	14981
74408943082 Würth Elektronik Midcom	FIXED IND 8.2UH 1.75A 81 MOHM	33
744155 Würth Elektronik Midcom	FIXED IND 220UH 7.1A 60 MOHM TH	0
744028000056 Würth Elektronik Midcom	FIXED IND 56NH 4.5A 15 MOHM SMD	1311
7443763521033 Würth Elektronik Midcom	FIXED IND 3.3UH 75A 0.4 MOHM TH	43

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