Fixed Inductors

Part Number	Description / PDF	Quantity
1120-221K-RC J.W. Miller / Bourns	FIXED IND 220UH 2.8A 150 MOHM TH	0
SDR0302-101KL J.W. Miller / Bourns	FIXED IND 100UH 260MA 2.85OHM SM	661
PM105-270M-RC J.W. Miller / Bourns	FIXED IND 27UH 1.75A 110MOHM SMD	0
SRU5028A-680Y J.W. Miller / Bourns	FIXED IND 68UH 560MA 550MOHM SMD	0
SRP1245C-1R5M J.W. Miller / Bourns	FIXED IND 1.5UH 27A 3.5 MOHM SMD	747
SRP1038A-470M J.W. Miller / Bourns	FIXED IND 47UH 3A 167 MOHM SMD	0
SDE1006A-101K J.W. Miller / Bourns	FIXED IND 100UH 1.3A 350MOHM SMD	192
PM43-220M-RC J.W. Miller / Bourns	FIXED IND 22UH 760MA 380MOHM SMD	21166
78F181J-RC J.W. Miller / Bourns	FIXED IND 180UH 140MA 6 OHM TH	263
RLB0608-680KL J.W. Miller / Bourns	FIXED IND 68UH 340MA 1.3 OHM TH	0
RLB1314-330KL J.W. Miller / Bourns	FIXED IND 33UH 1.8A 45 MOHM TH	3
SRN3015TA-470M J.W. Miller / Bourns	FIXED IND 47UH 400MA 1.2 OHM SMD	1679
SRR1280A-221K J.W. Miller / Bourns	FIXED IND 220UH 1.6A 400MOHM SMD	1488
CMH322522-4R7KL J.W. Miller / Bourns	FIXED IND 4.7UH 220MA 1.5OHM SMD	28
SRR1005-680Y J.W. Miller / Bourns	FIXED IND 68UH 820MA 340MOHM SMD	2458
SDR0906-271KL J.W. Miller / Bourns	FIXED IND 270UH 550MA 1 OHM SMD	0
SRR4011-R47YL J.W. Miller / Bourns	FIXED IND 470NH 3.2A 30 MOHM SMD	2364
CW100505-3N6J J.W. Miller / Bourns	FIXED INDUCTOR 3.6NH SMD	0
CE201210-82NJ J.W. Miller / Bourns	FIXED IND 82NH 300MA 900MOHM SMD	0
2310-H-RC J.W. Miller / Bourns	FIXED IND 56UH 10.2A 17 MOHM TH	325

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