TVS - Surge Protection Devices (SPDs)

Image	Part Number	Description / PDF	Quantity	Rfq
	BSPM1690WER Eaton	VARISTOR 690V 25KA MOD PLUG-IN	0
	SPP40SP3480DLG Eaton	SURGEPOD PRO TYPE1 SPD FOR 480V	0
	BSPD200600Y3K Eaton	SPD, 200KA, STD W/COUNTERPKG., N	0
	BSPD120480Y3P Eaton	SPD, 120KA, STD W/COUNTERPKG., N	0
	SPOD150S Eaton	SPOD FINAL ASSEMBLY	0
	BSPD400208Y3K Eaton	SPD, 400KA, STD W/COUNTERPKG., N	0
	BSPD300600D1P Eaton	SPD, 300KA, BASIC PKG., NEMA 4X	0
	BSPD120600Y1P Eaton	SPD, 120KA, BASIC PKG., NEMA 4X	0
	SPOD510LR Eaton	SPOD FINAL ASSEMBLY	0
	SPOD320L Eaton	SPOD FINAL ASSEMBLY	0
	BSPM1A75D100LVR Eaton	VARISTOR 40KA MODULE PLUG-IN	0
	BSPD200208Y3P Eaton	SPD, 200KA, STD W/COUNTERPKG., N	0
	BSPD400600Y2P Eaton	SPD, 400KA, STD PKG., NEMA 4X EN	0
	BSPM3385TNC Eaton	VARISTOR 40KA MODULE PLUG-IN	0
	BSPD400240D3P Eaton	SPD, 400KA, STD W/COUNTERPKG., N	0
	BSPD120240D3P Eaton	SPD, 120KA, STD W/COUNTERPKG., N	0
	BSPM1275TN Eaton	VARISTOR 230V 40KA MOD PLUG-IN	0
	SPOD320LT Eaton	SPOD FINAL ASSEMBLY	0
	SPP40SP3600WYG Eaton	SURGEPOD PRO TYPE1 SPD FOR 600 W	0
	BSPD120240D2P Eaton	SPD, 120KA, STD PKG., NEMA 4X EN	0

TVS - Surge Protection Devices (SPDs)

1. Overview

Transient Voltage Suppression (TVS) diodes and Surge Protection Devices (SPDs) are critical components for safeguarding electronic systems against voltage spikes and electrostatic discharge (ESD). TVS diodes are semiconductor devices designed for rapid response to transient events, while SPDs encompass a broader category of devices that protect power and signal lines in electrical systems. These components play a vital role in ensuring reliability in applications ranging from consumer electronics to industrial infrastructure.

2. Main Types and Functional Classification

Type	Functional Characteristics	Application Examples
TVS Diodes	Fast response time (ps/ns range), low clamping voltage, unidirectional/bidirectional configurations	Communication interfaces (USB, HDMI), automotive electronics, portable devices
Metal Oxide Varistors (MOVs)	High energy absorption, nonlinear voltage-current characteristics	Power strips, industrial equipment, building wiring systems
Gas Discharge Tubes (GDTs)	High surge current capability, multi-electrode design	Telecom infrastructure, lightning protection systems
Hybrid SPDs	Combination of TVS/MOV/GDT for multi-stage protection	Renewable energy systems, smart grids

3. Structure and Composition

TVS diodes typically employ a PN junction semiconductor structure with epitaxial layers for optimized clamping performance. MOVs consist of zinc oxide grains embedded in a ceramic matrix with grain boundary layers acting as insulating barriers. GDTs utilize hermetically sealed gas chambers with precision-spaced electrodes. Hybrid devices integrate multiple technologies in a single package with isolation barriers and thermal disconnect mechanisms.

4. Key Technical Specifications

Parameter	Significance	Typical Range
Clamping Voltage	Maximum voltage during surge event	5V-2000V
Response Time	Time to activate protection	0.1ps-10ns (TVS), 1 s-10 s (SPDs)
Maximum Peak Current	Surge current handling capability	10A-100kA
Operating Temperature	Environmental durability range	-55 C to +175 C
Parasitic Capacitance	Signal integrity impact factor	0.1pF-100nF

5. Application Areas

Telecommunications (base stations, optical transceivers)
Industrial automation (PLC systems, motor drives)
Renewable energy (solar inverters, wind turbine controllers)
Consumer electronics (smartphones, IoT devices)
Automotive (CAN bus protection, battery management systems)
Power distribution (smart meters, grid infrastructure)

6. Leading Manufacturers and Products

Manufacturer	Representative Products	Key Features
STMicroelectronics	SM6T Series	600W peak power, 5V-36V working voltage
Littelfuse	SP1012 Series	Ultra-low capacitance (0.25pF), USB4 protection
Bourns	CDSOT23-SM712	Bidirectional protection, RS-485 compatibility
TE Connectivity	ProTek Devices	Automotive qualified, AEC-Q101 certified

7. Selection Guidelines

Key considerations include:
- Working voltage and power requirements
- Environmental conditions (temperature, humidity)
- Surge current expectations (per IEC 61000-4-5)
- Signal bandwidth requirements (for high-speed interfaces)
- Compliance with industry standards (UL 1449, IEC 61643)
- Failure mode preferences (fail-short vs fail-open)
Example: For industrial Ethernet applications, select a bidirectional TVS with <1nS response time and 150V clamping voltage meeting IEEE 802.3 standards.

8. Industry Trends

Emerging trends include:
- Development of SiC/GaN-based TVS for high-frequency applications
- Integration with AI-powered predictive maintenance systems
- Miniaturization for wearable electronics (0201 package formats)
- Enhanced coordination between primary/secondary protection stages
- Adoption of TVS arrays for multi-line protection in 5G infrastructure
- Improved energy efficiency with lower leakage current devices