Fixed Inductors

Part Number	Description / PDF	Quantity
SCEP105L-1R4 Signal Transformer	FIXED IND 1.4UH 14A 4.1 MOHM SMD	0
SCEP125U-3R2 Signal Transformer	FIXED IND 3.2UH 13A 8 MOHM SMD	0
SCEP105S-R45 Signal Transformer	FIXED IND 450NH 18A 3.2 MOHM SMD	0
SCEP125-1R5 Signal Transformer	FIXED IND 1.5UH 17A 2.5 MOHM SMD	0
SCEP105H-3R0 Signal Transformer	FIXED IND 3UH 7.2A 23.8 MOHM SMD	0
SCEP105S-4R0 Signal Transformer	FIXED IND 4UH 7.5A 18 MOHM SMD	0
SCEP104S-1R8 Signal Transformer	FIXED IND 1.8UH 8A 18.6 MOHM SMD	0
CH-8 Signal Transformer	FIXED IND 30MH 8A 300 MOHM CHASS	8
CH-30 Signal Transformer	FIXED IND 4MH 30A 10 MOHM CHASS	0
SCEP104S-R22 Signal Transformer	FIXED IND 220NH 23A 2.6 MOHM SMD	0
SCEP105H-2R5 Signal Transformer	FIXED IND 2.5UH 7.8A 18 MOHM SMD	0
SCEP125H-7R2 Signal Transformer	FIXED IND 7.2UH 8.8A 13.5 MOHM	0
SCEP125U-R30 Signal Transformer	FIXED IND 300NH 23.5A 2.5 MOHM	0
SCEP105H-R80 Signal Transformer	FIXED IND 800NH 13.5A 5.3 MOHM	0
SCEP125U-1R4 Signal Transformer	FIXED IND 1.4UH 14A 3.8 MOHM SMD	0
SCEP125-1R2 Signal Transformer	FIXED IND 1.2UH 21A 2.5 MOHM SMD	0
SCEP105S-3R2 Signal Transformer	FIXED IND 3.2UH 8A 12.4 MOHM SMD	0
SCEP125U-4R3 Signal Transformer	FIXED IND 4.3UH 10.5A 11.4 MOHM	0
SCEP105H-R15 Signal Transformer	FIXED IND 150NH 20A 2.6 MOHM SMD	0
SCEP105S-R22 Signal Transformer	FIXED IND 220NH 20A 2.6 MOHM 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