Fixed Inductors

Part Number	Description / PDF	Quantity
CM322522-R12ML J.W. Miller / Bourns	FIXED IND 120NH 240MA 670MOHM SM	0
SRP0410-3R3K J.W. Miller / Bourns	FIXED IND 3.3UH 2.4A 120 MOHM	250
SRP0415-1R0K J.W. Miller / Bourns	FIXED IND 1UH 6.1A 22.5 MOHM SMD	3586
SRP0310-1R0K J.W. Miller / Bourns	FIXED IND 1UH 3.4A 58.5 MOHM SMD	160
SRR7045-390M J.W. Miller / Bourns	FIXED IND 39UH 1.1A 130 MOHM SMD	0
SRP5015TA-6R8M J.W. Miller / Bourns	FIXED IND 6.8UH 2.3A 171MOHM SMD	19
SRR6028-5R0Y J.W. Miller / Bourns	FIXED IND 5UH 2.4A 36 MOHM SMD	599
SRR4011-150YL J.W. Miller / Bourns	FIXED IND 15UH 900MA 400MOHM SMD	0
CM453232-681KL J.W. Miller / Bourns	FIXED IND 680UH 50MA 30 OHM SMD	1009
SRR0735A-390M J.W. Miller / Bourns	FIXED IND 39UH 950MA 250MOHM SMD	0
SRP1040-1R0M J.W. Miller / Bourns	FIXED IND 1UH 20A 3.5 MOHM SMD	398
SDR6603-471M J.W. Miller / Bourns	FIXED IND 470UH 150MA 5.1OHM SMD	774
5900-221-RC J.W. Miller / Bourns	FIXED IND 220UH 1.5A 185 MOHM TH	702
SDR0302-151KL J.W. Miller / Bourns	FIXED IND 150UH 200MA 4.6OHM SMD	1518
SDR1006-272KL J.W. Miller / Bourns	FIXED IND 2.7MH 140MA 11.6OHM SM	0
SRU2011-100Y J.W. Miller / Bourns	FIXED IND 10UH 520MA 740MOHM SMD	0
SRR1050A-181Y J.W. Miller / Bourns	FIXED IND 180UH 1A 420 MOHM SMD	0
RLB0913-123K J.W. Miller / Bourns	FIXED IND 12MH 115MA 33 OHM TH	448
6000-271K-RC J.W. Miller / Bourns	FIXED IND 270UH 900MA 750MOHM TH	490
SDE0604A-5R6M J.W. Miller / Bourns	FIXED IND 5.6UH 3.2A 75 MOHM SMD	4863

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