Fixed Inductors

Part Number	Description / PDF	Quantity
SRP4020FA-3R3M J.W. Miller / Bourns	FIXED IND 3.3UH 5.5A 38.3MOHM SM	979
PM75-100K-RC J.W. Miller / Bourns	FIXED IND 10UH 2.3A 70 MOHM SMD	500
SDR1030-330M J.W. Miller / Bourns	FIXED IND 33UH 1.1A 220 MOHM SMD	0
SRU6025A-221Y J.W. Miller / Bourns	FIXED IND 220UH 420MA 1.25OHM SM	600
PM3340-101M-RC J.W. Miller / Bourns	FIXED IND 100UH 1.2A 220MOHM SMD	708
CC453232-101KL J.W. Miller / Bourns	FIXED IND 100UH 180MA 4 OHM SMD	2489
PM1008S-101M-RC J.W. Miller / Bourns	FIXED IND 100UH 260MA 5.8OHM SMD	0
SRU5018-6R8Y J.W. Miller / Bourns	FIXED IND 6.8UH 1.45A 50MOHM SMD	42
RL187-332J-RC J.W. Miller / Bourns	FIXED IND 3.3MH 100MA 13 OHM TH	75
5900-271-RC J.W. Miller / Bourns	FIXED IND 270UH 1.4A 210 MOHM TH	0
SRR1280-6R1Y J.W. Miller / Bourns	FIXED IND 6.1UH 6.6A 18 MOHM SMD	0
SRU1038-5R0Y J.W. Miller / Bourns	FIXED IND 5UH 4.6A 14.5 MOHM SMD	0
2320-H-RC J.W. Miller / Bourns	FIXED IND 470UH 3.8A 130 MOHM TH	0
PM1608-330M-RC J.W. Miller / Bourns	FIXED IND 33UH 60MA 510 MOHM SMD	0
SRP0620-4R7K J.W. Miller / Bourns	FIXED IND 4.7UH 5.7A 39.6 MOHM	1590
SDR0302-561KL J.W. Miller / Bourns	FIXED IND 560UH 95MA 16 OHM SMD	1990
9230-82-RC J.W. Miller / Bourns	FIXED IND 390UH 55MA 35 OHM TH	0
SRR0905-180M J.W. Miller / Bourns	FIXED IND 18UH 1.6A 80 MOHM SMD	0
4604-RC J.W. Miller / Bourns	FIXED IND 1.5UH 1.8A 93 MOHM TH	595
SRR4028-5R6Y J.W. Miller / Bourns	FIXED IND 5.6UH 1.38A 85MOHM SMD	71

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