TVS - Surge Protection Devices (SPDs)

Part Number	Description / PDF	Quantity
BSP3-480 Thomas Research Products	LIGHTING SURGE PROTECTOR 480V	182
LSP05GI120S Wickmann / Littelfuse	LIGHTING SURGE PROTECT 120V SCRW	0
SPD-20-240P MEAN WELL	LIGHTING SURGE PROTECT 240V SCRW	76
SSP3-277 Thomas Research Products	LIGHT PROTECTOR SURGE PROT 277V	587
2730610000 Weidmuller	SURGE PROTECTION - OVP	55
LST2755VL2NT1 Wickmann / Littelfuse	VARISTOR SPD 275V 50KA SURGE	5
M50-120Y-B CITEL INC	120/208VAC THREE PHASES + NEUTRA	10
2730460000 Weidmuller	SURGE PROTECTION - OVP	1045
1210-1S-400 J.W. Miller / Bourns	SPD AC 1W+G 277VAC	0
1420-PV-1000 J.W. Miller / Bourns	SPD DC 2W+G 1000VAC	0
M50-277Y-B CITEL INC	277/480VAC THREE PHASES + NEUTRA	10
DLA2-24D3 CITEL INC	4-20MA TWO CHANNEL SPD	10
LSP05GI480SH Wickmann / Littelfuse	LIGHTING SURGE PROTECT 480V SCRW	0
LSP05480LLPM Wickmann / Littelfuse	LIGHTING SURGE PROTECT 480V SCRW	0
LSP05G240P Wickmann / Littelfuse	LIGHTING SURGE PROTECT 240V SCRW	237
2838843 Phoenix Contact	SURGE PROTECTION CONN TYPE 2	29105
FSSZOV421R Maida Development Company	THERMALLY PROTECTED MOV 420VAC	7
1210-3S-400 J.W. Miller / Bourns	SPD AC 3W+G 277VAC	0
LSP05240LLP Wickmann / Littelfuse	LIGHTING SURGE PROTECT 240V SCRW	0
1320-S-75 J.W. Miller / Bourns	SPD DC 2W+G 75VDC	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