Fixed Inductors

Part Number	Description / PDF	Quantity
NLCV25T-100K-EFR TDK Corporation	FIXED IND 10UH 360MA 1.32 OHM	8969
SLF12565T-100M4R8-PF TDK Corporation	FIXED IND 10UH 4.8A 24.2 MOHM	2223
MHQ1005P2N5ST000 TDK Corporation	FIXED IND 2.5NH 900MA 70 MOHM	0
VLS5045EX-1R0N-CA TDK Corporation	FIXED IND 1UH 5.1A 19.5MOHM SMD	3881
MHQ1005P39NHT000 TDK Corporation	FIXED IND 39NH 190MA 1.5 OHM SMD	0
SPM6545VT-680M-D TDK Corporation	FIXED IND 68UH 1.7A 340 MOHM SMD	21
MLG0603S0N4BTD25 TDK Corporation	FIXED IND 0.4NH 600MA 100 MOHM	0
SPM4030T-1R5M-HZ TDK Corporation	FIXED IND 1.5UH 3.6A 25.63MOHM	995
MLZ2012M6R8HTD25 TDK Corporation	FIXED IND 6.8UH 350MA 400 MOHM	23113
MLG0603P11NJTD25 TDK Corporation	FIXED IND 11NH 250MA 1 OHM SMD	0
VLM10555T-R45M110-3H TDK Corporation	FIXED IND 450NH 11A 2.6 MOHM SMD	0
VLS4012ET-150M-CA TDK Corporation	FIXED IND 15UH 1.05A 372 MOHM	1426
SPM3015T-1R0M TDK Corporation	FIXED IND 1UH 3.5A 52.9 MOHM SMD	894
SPM5030VT-4R7M-D TDK Corporation	FIXED IND 4.7UH 3.8A 59.1 MOHM	3405
VLF504015MT-2R2M-CA TDK Corporation	FIXED IND 2.2UH 2.6A 53 MOHM SMD	0
SPM4020T-1R5M-CA TDK Corporation	FIXED IND 1.5UH 4.1A 46.8 MOHM	0
MLG0603P4N2CTD25 TDK Corporation	FIXED IND 4.2NH 350MA 400 MOHM	0
NLCV25T-4R7M-EFRD TDK Corporation	FIXED IND 4.7UH 500MA 684 MOHM	0
CPL2508T6R8M TDK Corporation	FIXED IND 6.8UH 300MA 1.3 OHM	454
MHQ0402PSA0N7ST000 TDK Corporation	FIXED IND 0.7NH 600MA 150 MOHM	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