Fixed Inductors

Part Number	Description / PDF	Quantity
1110-3R9M-RC J.W. Miller / Bourns	FIXED IND 3.9UH 9A 6 MOHM TH	0
SDR6603-100M J.W. Miller / Bourns	FIXED IND 10UH 1.1A 160 MOHM SMD	600
SDR0805-100ML J.W. Miller / Bourns	FIXED IND 10UH 2.3A 70 MOHM SMD	1291
SRP0420-1R0K J.W. Miller / Bourns	FIXED IND 1UH 7.3A 18.5 MOHM SMD	16144
SRR0604-4R7ML J.W. Miller / Bourns	FIXED IND 4.7UH 2A 60 MOHM SMD	3741
PM74SB-221K-RC J.W. Miller / Bourns	FIXED IND 220UH 360MA 1.18OHM SM	0
SRR5018-220Y J.W. Miller / Bourns	FIXED IND 22UH 800MA 280MOHM SMD	514
CW252016-R15J J.W. Miller / Bourns	FIXED IND 150NH 500MA 700MOHM SM	1450
SDR1307-821KL J.W. Miller / Bourns	FIXED IND 820UH 750MA 1.3OHM SMD	1054
SRP1250-R22M J.W. Miller / Bourns	FIXED IND 220NH 45A 1 MOHM SMD	0
CMH322522-270KL J.W. Miller / Bourns	FIXED IND 27UH 80MA 5 OHM SMD	0
SRR0906-822KL J.W. Miller / Bourns	FIXED IND 8.2MH 80MA 31 OHM SMD	56
2200HT-120-H-RC J.W. Miller / Bourns	FIXED IND 12UH 10.9A 15 MOHM TH	0
RL181S-183J-RC J.W. Miller / Bourns	FIXED IND 18MH 21MA 17 OHM TH	179
SRR1206-470YL J.W. Miller / Bourns	FIXED IND 47UH 1.6A 130 MOHM SMD	170
SDR0604-820KL J.W. Miller / Bourns	FIXED IND 82UH 580MA 600MOHM SMD	525
SRU8045A-680Y J.W. Miller / Bourns	FIXED IND 68UH 1.25A 400MOHM SMD	0
SDR7030-470K J.W. Miller / Bourns	FIXED IND 47UH 700MA 340MOHM SMD	0
RL181S-103J-RC J.W. Miller / Bourns	FIXED IND 10MH 25MA 12.1 OHM TH	832
SRU1028-101Y J.W. Miller / Bourns	FIXED IND 100UH 850MA 365MOHM SM	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