Fixed Inductors

Part Number	Description / PDF	Quantity
74477001 Würth Elektronik Midcom	FIXED IND 1.2UH 12A 7 MOHM SMD	1333
74404032220 Würth Elektronik Midcom	FIXED IND 22UH 600MA 450 MOHM	7965
744765087A Würth Elektronik Midcom	FIXED IND 8.7NH 480MA 200 MOHM	5965
744917087 Würth Elektronik Midcom	FIXED IND 8.7NH 1.4A 54 MOHM SMD	0
744916137 Würth Elektronik Midcom	FIXED IND 37NH 470MA 480 MOHM	0
7444011480082 Würth Elektronik Midcom	FIXED IND 8.2UH 8.5A 9MOHM TH	72
74404043100A Würth Elektronik Midcom	FIXED IND 10UH 1.76A 89 MOHM	1058
744774215 Würth Elektronik Midcom	FIXED IND 150UH 460MA 1.1 OHM	1476
74404084151 Würth Elektronik Midcom	FIXED IND 150UH 910MA 478 MOHM	855
7447779127 Würth Elektronik Midcom	FIXED IND 27UH 1.24A 150 MOHM	610
744029100 Würth Elektronik Midcom	FIXED IND 10UH 650MA 470 MOHM	2415
7447462470 Würth Elektronik Midcom	FIXED IND 47UH 1.18A 340 MOHM TH	379
744916047 Würth Elektronik Midcom	FIXED IND 4.7NH 1.5A 60 MOHM SMD	0
744305040 Würth Elektronik Midcom	FIXED IND 400NH 26A 0.155 MOHM	456
744773047 Würth Elektronik Midcom	FIXED IND 4.7UH 1.82A 110 MOHM	1642
744775215 Würth Elektronik Midcom	FIXED IND 150UH 600MA 640 MOHM	398
744917033 Würth Elektronik Midcom	FIXED IND 3.3NH 1.9A 24 MOHM SMD	0
7443556350 Würth Elektronik Midcom	FIXED IND 3.5UH 22.5A 3.1 MOHM	448
7440660035 Würth Elektronik Midcom	FIXED IND 3.5UH 5.8A 15 MOHM SMD	745
74456147 Würth Elektronik Midcom	FIXED IND 47UH 1.8A 190 MOHM SMD	1195

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