Fixed Inductors

Part Number	Description / PDF	Quantity
7447773681 Würth Elektronik Midcom	FIXED IND 680UH 360MA 2.3 OHM	0
74479276210 Würth Elektronik Midcom	FIXED IND 1UH 2A 75 MOHM SMD	4645
7449150146 Würth Elektronik Midcom	FIXED IND 146NH 19A 3.33 MOHM	523
744031100 Würth Elektronik Midcom	FIXED IND 10UH 740MA 205 MOHM	528
744117 Würth Elektronik Midcom	FIXED IND 390UH 2A 250 MOHM TH	0
744761133C Würth Elektronik Midcom	FIXED IND 33NH 600MA 200 MOHM	669
744765130A Würth Elektronik Midcom	FIXED IND 30NH 400MA 300 MOHM	3504
7447709001 Würth Elektronik Midcom	FIXED IND 1UH 13A 6 MOHM SMD	250
744760112C Würth Elektronik Midcom	FIXED IND 12NH 600MA 150 MOHM	1900
744761168C Würth Elektronik Midcom	FIXED IND 68NH 600MA 350 MOHM	11502
744765110GA Würth Elektronik Midcom	FIXED IND 10NH 480MA 195 MOHM	2950
744786243A Würth Elektronik Midcom	FIXED IND 430NH 150MA 3.4 OHM	1000
7447462152 Würth Elektronik Midcom	FIXED IND 1.5MH 190MA 8 OHM TH	910
784776168 Würth Elektronik Midcom	FIXED IND 68UH 1.19A 220 MOHM	0
744764039 Würth Elektronik Midcom	FIXED IND 3.9UH 250MA 1.3 OHM	0
74459147 Würth Elektronik Midcom	FIXED IND 47UH 2.8A 97 MOHM SMD	0
7440450015 Würth Elektronik Midcom	FIXED IND 1.5UH 1.75A 90 MOHM	3
744750420047 Würth Elektronik Midcom	FIXED IND 4.7UH 8.7A 8.5 MOHM	0
74404031470A Würth Elektronik Midcom	FIXED IND 47UH 480MA 1.253 OHM	1596
74437336100 Würth Elektronik Midcom	FIXED IND 10UH 2.4A 128 MOHM SMD	4284

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