Fixed Inductors

Part Number	Description / PDF	Quantity
744731680 Würth Elektronik Midcom	FIXED IND 68UH 1.5A 200 MOHM TH	0
744306025 Würth Elektronik Midcom	FIXED IND 250NH 25A 0.26 MOHM	0
744383240056 Würth Elektronik Midcom	FIXED IND 560NH 3.3A 49 MOHM SMD	0
78438356010 Würth Elektronik Midcom	FIXED IND 1UH 7.2A 15 MOHM SMD	4543
744031004 Würth Elektronik Midcom	FIXED IND 4.7UH 1.2A 105 MOHM	19814
74404054047 Würth Elektronik Midcom	FIXED IND 4.7UH 3A 30 MOHM SMD	7806
744910038 Würth Elektronik Midcom	FIXED IND 3.85NH 1.6A 6 MOHM SMD	1787
7447860247 Würth Elektronik Midcom	FIXED IND 470NH 150MA 2.6 OHM	3679
744772471 Würth Elektronik Midcom	FIXED IND 470UH 430MA 890 MOHM	0
744316068 Würth Elektronik Midcom	FIXED IND 680NH 12.75A 4 MOHM	1421
744031010 Würth Elektronik Midcom	FIXED IND 1UH 2A 37 MOHM SMD	1224
74477310 Würth Elektronik Midcom	FIXED IND 10UH 1.45A 182 MOHM	520
74479977147 Würth Elektronik Midcom	FIXED IND 470NH 2.2A 65 MOHM SMD	0
744776147 Würth Elektronik Midcom	FIXED IND 47UH 1.45A 170 MOHM	392
744916068 Würth Elektronik Midcom	FIXED IND 6.8NH 1.5A 55 MOHM SMD	0
744762068A Würth Elektronik Midcom	FIXED IND 6.8NH 1A 60 MOHM SMD	0
784773082 Würth Elektronik Midcom	FIXED IND 8.2UH 1.5A 146 MOHM	0
74404063022 Würth Elektronik Midcom	FIXED IND 2.2UH 3.75A 20 MOHM	3430
744383340068 Würth Elektronik Midcom	FIXED IND 680NH 3.5A 43.2 MOHM	839
744138 Würth Elektronik Midcom	FIXED IND 727UH 3.5A 240 MOHM TH	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