Fixed Inductors

Part Number	Description / PDF	Quantity
SDR0604-221KL J.W. Miller / Bourns	FIXED IND 220UH 350MA 1.57OHM SM	21814
SRP0412-R68K J.W. Miller / Bourns	FIXED IND 680NH 5.6A 25 MOHM SMD	4300
PM42S-100-RC J.W. Miller / Bourns	FIXED IND 10UH 1.3A 150 MOHM SMD	0
5900-822-RC J.W. Miller / Bourns	FIXED IND 8.2MH 260MA 6 OHM TH	157
SRR6603-4R7ML J.W. Miller / Bourns	FIXED IND 4.7UH 1.4A 60 MOHM SMD	0
PM1812-R22K-RC J.W. Miller / Bourns	FIXED IND 220NH 665MA 250MOHM SM	0
SRR4028-121Y J.W. Miller / Bourns	FIXED IND 120UH 470MA 700MOHM SM	639
SRR1206-680YL J.W. Miller / Bourns	FIXED IND 68UH 1.3A 170 MOHM SMD	600
SRR4828A-820M J.W. Miller / Bourns	FIXED IND 82UH 850MA 480MOHM SMD	97
PM105-331K-RC J.W. Miller / Bourns	FIXED IND 330UH 520MA 1.15OHM SM	0
1140-101K-RC J.W. Miller / Bourns	FIXED IND 100UH 10.5A 25 MOHM TH	1416
SDE0604A-2R7M J.W. Miller / Bourns	FIXED IND 2.7UH 4A 55 MOHM SMD	583
RLB0608-391KL J.W. Miller / Bourns	FIXED IND 390UH 150MA 6 OHM TH	0
SDE0805A-220M J.W. Miller / Bourns	FIXED IND 22UH 2.35A 110MOHM SMD	18
RL181S-102J-RC J.W. Miller / Bourns	FIXED IND 1MH 90MA 3.4 OHM TH	1325
PM0603-12NJ-RC J.W. Miller / Bourns	FIXED IND 12NH 700MA 130MOHM SMD	0
CW105550A-10NJ J.W. Miller / Bourns	FIXED IND 10NH 480MA 195MOHM SMD	9645
SRU5018-4R7Y J.W. Miller / Bourns	FIXED IND 4.7UH 2A 36 MOHM SMD	1123
PM2110-391K-RC J.W. Miller / Bourns	FIXED IND 390UH 3.1A 98 MOHM SMD	574
SRP1238A-R47M J.W. Miller / Bourns	FIXED IND 470NH 32A 1.8 MOHM SMD	300

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