Fixed Inductors

Part Number	Description / PDF	Quantity
SRN5040TA-3R3M J.W. Miller / Bourns	FIXED IND 3.3UH 3.5A 24 MOHM SMD	17
P1330R-224H API Delevan	FIXED IND 220UH 223MA 2.648 OHM	0
1210R-331J API Delevan	FIXED IND 330NH 720MA 400 MOHM	0
PA4301.562NLT PulseLarsen Antenna	FIXED IND 5.6UH 2.13A 45.5 MOHM	0
SP1812R-393J API Delevan	FIXED IND 39UH 354MA 1.6 OHM SMD	0
LQW15AN6N2C80D TOKO / Murata	FIXED IND 6.2NH 1.6A 56 MOHM SMD	0
MLZ2012M100WT000 TDK Corporation	FIXED IND 10UH 350MA 470 MOHM	130118
LQW15AN9N1J00D TOKO / Murata	FIXED IND 9.1NH 540MA 140 MOHM	6704
HK2125R10K-T TAIYO YUDEN	FIXED IND 100NH 300MA 900 MOHM	0
LQM18NNR82K00D TOKO / Murata	FIXED IND 820NH 35MA 2.1 OHM SMD	5810
SCIHP0718-1R0M Signal Transformer	FIXED IND 1UH 7A 18.5 MOHM SMD	827
HCTI-180-4.8 Signal Transformer	FIXED IND 180UH 4.8A 78 MOHM TH	0
CB2012T220K TAIYO YUDEN	FIXED IND 22UH 280MA 2.21 OHM	34181
32150C Murata Power Solutions	FIXED IND 15UH 3.7A 24 MOHM TH	0
1210R-472H API Delevan	FIXED IND 4.7UH 352MA 1.5 OHM	0
AISC-0603-R0075J-T Abracon	FIXED IND 7.5NH 700MA 95 MOHM	2573
74438357012 Würth Elektronik Midcom	FIXED IND 1.2UH 7A 15.5 MOHM SMD	766
RL875-272K-RC J.W. Miller / Bourns	FIXED IND 2.7MH 160MA 8.72OHM TH	0
AX104R-6R8 Triad Magnetics	FIXED IND 6.8UH 4.8A 19.5 MOHM	0
SRU8043-100Y J.W. Miller / Bourns	FIXED IND 10UH 3.5A 30 MOHM SMD	4958

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