Fixed Inductors

Part Number	Description / PDF	Quantity
1540M03 Hammond Manufacturing	FIXED IND 125UH 2.75A 120 MOHM	35
195P20 Hammond Manufacturing	FIXED IND 30MH 20A 130 MOHM CHAS	1
157R Hammond Manufacturing	FIXED IND 2H 200MA 57 OHM CHASS	12
1538M13 Hammond Manufacturing	FIXED IND 100UH 6.8A 38 MOHM TH	72
1536Z Hammond Manufacturing	FIXED IND 1MH 1A 550 MOHM TH	165
154G Hammond Manufacturing	FIXED IND 9H 40MA 700 OHM CHASS	17
1540M13 Hammond Manufacturing	FIXED IND 700UH 2.25A 420 MOHM	0
1536S Hammond Manufacturing	FIXED IND 68UH 5A 54 MOHM TH	64
1538M04 Hammond Manufacturing	FIXED IND 50UH 5.6A 40 MOHM TH	14
1540M04 Hammond Manufacturing	FIXED IND 275UH 2A 240 MOHM TH	0
1532H Hammond Manufacturing	FIXED IND 100UH 400MA 3 OHM TH	315
1539M10 Hammond Manufacturing	FIXED IND 5UH 20A 5 MOHM TH	23
1539M18 Hammond Manufacturing	FIXED IND 2.5MH 1.6A 690 MOHM TH	15
193B Hammond Manufacturing	FIXED IND 12H 100MA 155 OHM CHAS	3
195T5 Hammond Manufacturing	FIXED IND 100MH 5A 640 MOHM CHAS	141
1540M25 Hammond Manufacturing	FIXED IND 8MH 1A 3.34 OHM TH	0
1540M20 Hammond Manufacturing	FIXED IND 4.5MH 1.25A 2.64 OHM	28
193Q Hammond Manufacturing	FIXED IND 10H 500MA 53 OHM CHASS	8
193N Hammond Manufacturing	FIXED IND 3H 500MA 35 OHM CHASS	6
1540M10 Hammond Manufacturing	FIXED IND 1MH 1.5A 980 MOHM TH	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