Fixed Inductors

Part Number	Description / PDF	Quantity
B82432T1183K000 TDK EPCOS	FIXED IND 18UH 550MA 600 MOHM	0
B82472P6103M000 TDK EPCOS	FIXED IND 10UH 1.9A 55 MOHM SMD	3289
B78148S1155J009 TDK EPCOS	FIXED IND 1.5MH 100MA 23 OHM TH	0
B82442T1225J50 TDK EPCOS	FIXED IND 2.2MH 100MA 22.5 OHM	0
B82442A1272K000 TDK EPCOS	FIXED IND 2.7UH 1.2A 56 MOHM SMD	0
B78108E1101M000 TDK EPCOS	FIXED IND 100NH 7.3A 15 MOHM TH	2242
B82462A4332M000 TDK EPCOS	FIXED IND 3.3UH 2A 60 MOHM SMD	52
B82462A4472M000 TDK EPCOS	FIXED IND 4.7UH 1.65A 80 MOHM	10757
B82498F1152J000 TDK EPCOS	FIXED IND 1.5UH 200MA 700 MOHM	4030
B82442A1333K000 TDK EPCOS	FIXED IND 33UH 400MA 500 MOHM	3591
B82498F1682J000 TDK EPCOS	FIXED IND 6.8UH 80MA 4.7 OHM SMD	8399
B82498F3390G001 TDK EPCOS	FIXED IND 39NH 600MA 120 MOHM	0
B78148S1472K009 TDK EPCOS	FIXED IND 4.7UH 820MA 340 MOHM	0
B82477G4473M000 TDK EPCOS	FIXED IND 47UH 2.5A 82 MOHM SMD	4681
B82141A1824J000 TDK EPCOS	FIXED IND 820UH 60MA 25 OHM TH	0
B82442H1183K000 TDK EPCOS	FIXED IND 18UH 740MA 290 MOHM	0
B82432C1393J000 TDK EPCOS	FIXED IND 39UH 220MA 2.05 OHM	0
B82477G2105M000 TDK EPCOS	FIXED IND 1MH 400MA 1.53 OHM SMD	0
B82141A1332K000 TDK EPCOS	FIXED IND 3.3UH 580MA 300 MOHM	0
B82133A5152M000 TDK EPCOS	FIXED IND 25UH 1.5A 320 MOHM TH	629

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