Fixed Inductors

Part Number	Description / PDF	Quantity
SRU8028A-100Y J.W. Miller / Bourns	FIXED IND 10UH 2.6A 57 MOHM SMD	3000
PM0603-2N2-RC J.W. Miller / Bourns	FIXED IND 2.2NH 700MA 80MOHM SMD	0
SRN4018-101M J.W. Miller / Bourns	FIXED IND 100UH 420MA 1.596 OHM	101
SDR1307-5R6ML J.W. Miller / Bourns	FIXED IND 5.6UH 6.5A 15 MOHM SMD	736
CW160808-18NG J.W. Miller / Bourns	FIXED IND 18NH 700MA 170MOHM SMD	0
CW252016-R33G J.W. Miller / Bourns	FIXED IND 330NH 500MA 1.05OHM SM	420
77F680J-TR-RC J.W. Miller / Bourns	FIXED IND 68UH 305MA 1.8 OHM TH	0
SRR0906-2R7ML J.W. Miller / Bourns	FIXED IND 2.7UH 3.2A 32 MOHM SMD	0
SRP3012TA-100M J.W. Miller / Bourns	FIXED IND 10UH 1A 550 MOHM SMD	1449
SRR0805-681K J.W. Miller / Bourns	FIXED IND 680UH 170MA 3.4OHM SMD	0
SRU5028-2R2Y J.W. Miller / Bourns	FIXED IND 2.2UH 3.2A 21 MOHM SMD	0
SDR0503-821KL J.W. Miller / Bourns	FIXED IND 820UH 120MA 10 OHM SMD	0
PQ2614BLA-220K J.W. Miller / Bourns	FIXED IND 22UH 30A 1.6 MOHM SMD	76
SRN5040-4R7M J.W. Miller / Bourns	FIXED IND 4.7UH 3.1A 35 MOHM SMD	9652
2100LL-180-H-RC J.W. Miller / Bourns	FIXED IND 18UH 10.1A 7 MOHM TH	725
RL875-470K-RC J.W. Miller / Bourns	FIXED IND 47UH 1.3A 150 MOHM TH	0
SRR0905-221K J.W. Miller / Bourns	FIXED IND 220UH 470MA 780MOHM SM	0
SRR4528A-270M J.W. Miller / Bourns	FIXED IND 27UH 1.06A .197OHM SMD	186
2200HT-180-H-RC J.W. Miller / Bourns	FIXED IND 18UH 9.7A 18 MOHM TH	0
SRR0805-330Y J.W. Miller / Bourns	FIXED IND 33UH 920MA 240MOHM SMD	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