Fixed Inductors

Part Number	Description / PDF	Quantity
744066681 Würth Elektronik Midcom	FIXED IND 680UH 460MA 2.15 OHM	2832
74479763222 Würth Elektronik Midcom	FIXED IND 2.2UH 800MA 375 MOHM	3366
7443762504022 Würth Elektronik Midcom	FIXED IND 2.2UH 30A 1.96 MOHM TH	200
744784012 Würth Elektronik Midcom	FIXED IND 1.2NH 300MA 120 MOHM	200
744761020A Würth Elektronik Midcom	FIXED IND 2NH 700MA 80 MOHM SMD	3914
7447798360 Würth Elektronik Midcom	FIXED IND 3.6UH 12A 5.95 MOHM	440
7447789218 Würth Elektronik Midcom	FIXED IND 180UH 490MA 1.45 OHM	0
7447783220 Würth Elektronik Midcom	FIXED IND 22UH 1.75A 115 MOHM	435
744308020 Würth Elektronik Midcom	FIXED IND 200NH 25A 0.37 MOHM	618
74456015 Würth Elektronik Midcom	FIXED IND 1.5UH 7.2A 9 MOHM SMD	0
744323020 Würth Elektronik Midcom	FIXED IND 200NH 22A 0.82 MOHM	0
7447709270 Würth Elektronik Midcom	FIXED IND 27UH 4.6A 40 MOHM SMD	1360
744761168A Würth Elektronik Midcom	FIXED IND 68NH 600MA 340MOHM SMD	3000
74477007 Würth Elektronik Midcom	FIXED IND 7.6UH 7.4A 20 MOHM SMD	477
784775115 Würth Elektronik Midcom	FIXED IND 15UH 1.93A 90 MOHM SMD	0
78477310 Würth Elektronik Midcom	FIXED IND 10UH 1.45A 182 MOHM	0
744765068GA Würth Elektronik Midcom	FIXED IND 6.8NH 680MA 83 MOHM	2960
7443552100 Würth Elektronik Midcom	FIXED IND 1UH 16A 3.3 MOHM SMD	1369
744732331 Würth Elektronik Midcom	FIXED IND 330UH 600MA 1.2 OHM TH	131
74457047 Würth Elektronik Midcom	FIXED IND 4.7UH 8.5A 11 MOHM SMD	250

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