Fixed Inductors

Part Number	Description / PDF	Quantity
74437321047 Würth Elektronik Midcom	FIXED IND 4.7UH 1.9A 145 MOHM	3333
744916125 Würth Elektronik Midcom	FIXED IND 25NH 700MA 300 MOHM	0
7443551331 Würth Elektronik Midcom	FIXED IND 33UH 5.5A 30.5 MOHM	3033
744761075C Würth Elektronik Midcom	FIXED IND 7.5NH 700MA 100 MOHM	2960
7447471470 Würth Elektronik Midcom	FIXED IND 47UH 3A 88 MOHM TH	1390
7447860027 Würth Elektronik Midcom	FIXED IND 2.7NH 300MA 100 MOHM	3435
7440329470 Würth Elektronik Midcom	FIXED IND 47UH 170MA 1.69 OHM	1958
784776147 Würth Elektronik Midcom	FIXED IND 47UH 1.45A 170 MOHM	0
78438357010 Würth Elektronik Midcom	FIXED IND 1UH 7.4A 13.5MOHM SMD	336
744760127C Würth Elektronik Midcom	FIXED IND 27NH 500MA 250 MOHM	390
744900020 Würth Elektronik Midcom	FIXED IND 2NH 200MA 700 MOHM SMD	0
744917127 Würth Elektronik Midcom	FIXED IND 27NH 780MA 200 MOHM	0
7443739650033 Würth Elektronik Midcom	FIXED IND 330NH 29.5A 0.8 MOHM	835
744778001 Würth Elektronik Midcom	FIXED IND 1UH 5.37A 12 MOHM SMD	1664
750341479 Würth Elektronik Midcom	FIXED IND 2.2MH 1.16 OHM TH	0
74404086102 Würth Elektronik Midcom	FIXED IND 1MH 480MA 2.35 OHM SMD	2391
744032680 Würth Elektronik Midcom	FIXED IND 68UH 130MA 3.8 OHM SMD	808
7847709101 Würth Elektronik Midcom	FIXED IND 100UH 2.2A 120 MOHM	0
744053100 Würth Elektronik Midcom	FIXED IND 10UH 1.5A 70 MOHM SMD	1535
744373360033 Würth Elektronik Midcom	FIXED IND 330NH 10.6A 5 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