Fixed Inductors

Part Number	Description / PDF	Quantity
744762118GA Würth Elektronik Midcom	FIXED IND 18NH 1A 100MOHM SMD	1600
74405024033 Würth Elektronik Midcom	FIXED IND 3.3UH 1.3A 163 MOHM	379
7687709332 Würth Elektronik Midcom	FIXED IND 3.3MH 370MA 5.2 OHM	371
744917212 Würth Elektronik Midcom	FIXED IND 120NH 420MA 720 MOHM	0
744758312A Würth Elektronik Midcom	FIXED IND 1.2UH 760MA 500 MOHM	97
784773133 Würth Elektronik Midcom	FIXED IND 33UH 860MA 540 MOHM	0
74404042220 Würth Elektronik Midcom	FIXED IND 22UH 700MA 290 MOHM	1918
74477826 Würth Elektronik Midcom	FIXED IND 680UH 220MA 5.73 OHM	379
74479887124C Würth Elektronik Midcom	FIXED IND 240NH 3.8A 24 MOHM SMD	0
7447041 Würth Elektronik Midcom	FIXED IND 68UH 800MA 100 MOHM TH	0
744776118 Würth Elektronik Midcom	FIXED IND 18UH 2.36A 90 MOHM SMD	2091
744383130033 Würth Elektronik Midcom	FIXED IND 330NH 1.9A 84 MOHM SMD	0
7447786002 Würth Elektronik Midcom	FIXED IND 2.2UH 3.5A 49 MOHM SMD	260
74404300047 Würth Elektronik Midcom	FIXED IND 470NH 3.8A 16 MOHM SMD	486
744916116 Würth Elektronik Midcom	FIXED IND 16NH 850MA 130 MOHM	0
744043221 Würth Elektronik Midcom	FIXED IND 220UH 340MA 1.25 OHM	739
750311907 Würth Elektronik Midcom	FIXED IND 1.2MH 200MA 1.1 OHM TH	0
744750340150 Würth Elektronik Midcom	FIXED IND 15UH 5.6A 20 MOHM TH	90
7447820127 Würth Elektronik Midcom	FIXED IND 27NH 120MA 1.35 OHM	14900
7687714681 Würth Elektronik Midcom	FIXED IND 680UH 550MA 2.25 OHM	486

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