Fixed Inductors

Part Number	Description / PDF	Quantity
744303015 Würth Elektronik Midcom	FIXED IND 155NH 31A 0.325 MOHM	1557
744784027A Würth Elektronik Midcom	FIXED IND 2.7NH 300MA 170 MOHM	13215
74479876210 Würth Elektronik Midcom	FIXED IND 1UH 1.5A 70 MOHM SMD	0
744784022 Würth Elektronik Midcom	FIXED IND 2.2NH 300MA 160 MOHM	10000
744042331 Würth Elektronik Midcom	FIXED IND 330UH 150MA 4.5 OHM	260
7447797250 Würth Elektronik Midcom	FIXED IND 2.5UH 8.4A 10.2 MOHM	196
7447714680 Würth Elektronik Midcom	FIXED IND 68UH 1.9A 132 MOHM SMD	13030
7447783047 Würth Elektronik Midcom	FIXED IND 4.7UH 3.3A 35 MOHM SMD	0
7443330047 Würth Elektronik Midcom	FIXED IND 470NH 20.5A 1.85 MOHM	400
744045100 Würth Elektronik Midcom	FIXED IND 10UH 950MA 300 MOHM	1963
744043008 Würth Elektronik Midcom	FIXED IND 8.2UH 1.25A 100 MOHM	415
744917222 Würth Elektronik Midcom	FIXED IND 220NH 280MA 2 OHM SMD	0
744762312A Würth Elektronik Midcom	FIXED IND 1.2UH 230MA 1.3 OHM	0
744765127A Würth Elektronik Midcom	FIXED IND 27NH 400MA 298 MOHM	8047
74437356100 Würth Elektronik Midcom	FIXED IND 10UH 3.7A 71.2 MOHM	276
7447773047 Würth Elektronik Midcom	FIXED IND 4.7UH 3.6A 26 MOHM SMD	1878
7447714151 Würth Elektronik Midcom	FIXED IND 150UH 1.2A 300 MOHM	332
744732470 Würth Elektronik Midcom	FIXED IND 47UH 1.8A 140 MOHM TH	138
74438356047HT Würth Elektronik Midcom	FIXED IND 4.7UH 3A 74.8MOHM SMD	474
7444011715220 Würth Elektronik Midcom	FIXED IND 22UH 10A 7MOHM TH	90

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