Fixed Inductors

Part Number	Description / PDF	Quantity
B82144B2332K000 TDK EPCOS	FIXED IND 3.3UH 3.5A 65 MOHM TH	1812
B78148S1393K000 TDK EPCOS	FIXED IND 39UH 470MA 1.02 OHM TH	0
B82462G4223M000 TDK EPCOS	FIXED IND 22UH 1.05A 150 MOHM	7121
B82477P2332M000 TDK EPCOS	FIXED IND 3.3UH 6.7A 14 MOHM SMD	573
B82472G6102M000 TDK EPCOS	FIXED IND 1UH 3.6A 15 MOHM SMD	3544
B82477G2333M000 TDK EPCOS	FIXED IND 33UH 2.1A 57 MOHM SMD	0
B82442A1225J000 TDK EPCOS	FIXED IND 2.2MH 55MA 28 OHM SMD	60
B82442T1335K000 TDK EPCOS	FIXED IND 3.3MH 85MA 32.8 OHM	0
B78148S1822K009 TDK EPCOS	FIXED IND 8.2UH 690MA 480 MOHM	0
B82442H1123K000 TDK EPCOS	FIXED IND 12UH 880MA 200 MOHM	0
B82422H1152K000 TDK EPCOS	FIXED IND 1.5UH 900MA 140 MOHM	3860
B78108S1273K009 TDK EPCOS	FIXED IND 27UH 530MA 830 MOHM TH	0
B82132A5701M000 TDK EPCOS	FIXED IND 23UH 700MA 730 MOHM TH	2175
B82422A3120J100 TDK EPCOS	FIXED IND 12NH 700MA 100 MOHM	0
B82479A1683M000 TDK EPCOS	FIXED IND 68UH 2.3A 130 MOHM SMD	0
B78108S1474J009 TDK EPCOS	FIXED IND 470UH 170MA 7.9 OHM TH	0
B82141A1184J000 TDK EPCOS	FIXED IND 180UH 135MA 5.3 OHM TH	0
B82482M1501N000 TDK EPCOS	PCM120T-R50N-D; 12.4X13.1X11.5 M	0
B82442H1184J000 TDK EPCOS	FIXED IND 180UH 270MA 2.24 OHM	0
B82442T1222K000 TDK EPCOS	FIXED IND 2.2UH 2.71A 38 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