Fixed Inductors

Part Number	Description / PDF	Quantity
1812-820M API Delevan	FIXED IND 82NH 700MA 250 MOHM	0
SRR1205-271KL J.W. Miller / Bourns	FIXED IND 270UH 600MA 1 OHM SMD	0
ASPIAIG-S8050-151M-T Abracon	FIXED IND 150UH 1A 480 MOHM SMD	71
IMC1812ER121J Vishay / Dale	FIXED IND 120UH 110MA 8 OHM SMD	0
B82472P6682M000 TDK EPCOS	FIXED IND 6.8UH 2.15A 42 MOHM	950
LQH43MN390K03L TOKO / Murata	FIXED IND 39UH 240MA 1.4 OHM SMD	0
LQH2MCN120K02L TOKO / Murata	FIXED IND 12UH 210MA 1.82 OHM	0
P1330R-394G API Delevan	FIXED IND 390UH 171MA 5.64 OHM	0
4590-275K API Delevan	FIXED IND 2.7MH 560MA 2.13 OHM	0
NRS5014T220MMGG TAIYO YUDEN	FIXED IND 22UH 550MA 540 MOHM	0
110001101 Würth Elektronik Midcom	FIXED IND 10.4UH 2.5A 33 MOHM	1050
RLB0912-2R2ML J.W. Miller / Bourns	FIXED IND 2.2UH 5.3A 10 MOHM TH	917
CMH322522-470KL J.W. Miller / Bourns	FIXED IND 47UH 60MA 7 OHM SMD	0
AISC-0402-11NJ-T Abracon	FIXED IND 11NH 640MA 120 MOHM	7660
SRR1050A-6R8Y J.W. Miller / Bourns	FIXED IND 6.8UH 5.4A 19 MOHM SMD	261
VLS201612HBX-R24M-1 TDK Corporation	FIXED IND 240NH 5.65A 29 MOHM	7604
SRR4528A-331M J.W. Miller / Bourns	FIXED IND 330UH 320MA 2.16 OHM	16
RLB1314-680KL J.W. Miller / Bourns	FIXED IND 68UH 1.2A 92 MOHM TH	0
MLG1005S0N4CTD25 TDK Corporation	FIXED IND 0.4NH 1A 100 MOHM SMD	0
7443082018A Würth Elektronik Midcom	FIXED IND 180NH 65A 0.15MOHM SMD	733

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