Fixed Inductors

Part Number	Description / PDF	Quantity
1540M21 Hammond Manufacturing	FIXED IND 250UH 8A 41 MOHM TH	16
193P Hammond Manufacturing	FIXED IND 5H 500MA 26 OHM CHASS	4
157Q Hammond Manufacturing	FIXED IND 3.5H 150MA 98 OHM CHAS	2
1540M16 Hammond Manufacturing	FIXED IND 125UH 7.75A 32 MOHM TH	0
1540M18 Hammond Manufacturing	FIXED IND 1.1MH 2.5A 330 MOHM TH	37
1536W Hammond Manufacturing	FIXED IND 125UH 3.5A 80 MOHM TH	438
1540M06 Hammond Manufacturing	FIXED IND 25UH 9A 12 MOHM TH	3
1540M09 Hammond Manufacturing	FIXED IND 800UH 1.75A 640 MOHM	242
193S Hammond Manufacturing	FIXED IND 1H 1A 5.75 OHM CHASSIS	2
1540M08 Hammond Manufacturing	FIXED IND 400UH 2.25A 330 MOHM	0
195R20 Hammond Manufacturing	FIXED IND 50MH 20A 130 MOHM CHAS	3
1532C Hammond Manufacturing	FIXED IND 24UH 800MA 340 MOHM TH	1004
158Q Hammond Manufacturing	FIXED IND 5H 150MA 105 OHM CHASS	17
159ZE Hammond Manufacturing	FIXED IND 28MH 3A 430 MOHM CHASS	22
1538M23 Hammond Manufacturing	FIXED IND 27UH 15A 10 MOHM TH	3
155G Hammond Manufacturing	FIXED IND 7H 40MA 340 OHM CHASS	13
154B Hammond Manufacturing	FIXED IND 3MH 1.5A 140 MOHM CHAS	12
1536X Hammond Manufacturing	FIXED IND 250UH 2.5A 170 MOHM TH	833
1539M08 Hammond Manufacturing	FIXED IND 1MH 1.3A 801 MOHM TH	9
193J Hammond Manufacturing	FIXED IND 10H 200MA 82 OHM CHASS	6

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