Overview
From city street cameras and park monitoring equipment to home smart cameras, modern security systems not only need to continuously provide high-definition video capture, but also integrate multiple functions such as network communication, audio acquisition, storage, sensors, and intelligent analysis.
I. Major Transient Threats Faced by Security Monitoring Systems
- Lightning Surge
Outdoor cameras are usually installed in open environments such as building facades and road poles, making them susceptible to surges induced by lightning.
Potential Impacts:
- Camera power module damage
- Network communication chip breakdown
- PoE interface failure
- System disconnection or restart
Therefore, the power input and communication interface typically require protection schemes with high surge withstand capabilities.
- Electrostatic Discharge (ESD)
During equipment installation, maintenance, or user operation, static electricity from the human body may enter the internal circuitry through the interface.
ESD may affect:
- Network PHY chip
- MCU control unit
- Audio chip
- Storage interface
- Sensor interface
Due to the trend of high-speed communication and miniaturization, chip withstand voltage is decreasing, thus requiring low-capacitance, high-response ESD protection devices.
II. Security Monitoring System Protection Scheme Design
Semiware recommends that engineers adopt an EMC forward design concept, selecting appropriate TVS diodes, ESD protection devices, gas discharge tubes (GDTs), and PPTC protection devices according to the characteristics of different interfaces to provide multi-layer protection for security monitoring systems.
- Network Communication Interface Protection
Network interfaces (such as Gigabit Ethernet, PoE) are important channels for security cameras to connect to the external environment and are also the main path for surges to enter the device.
Design Recommendations:
- GDTs are used to release high-energy lightning surges.
- ESD diodes are used to quickly suppress static electricity.
- PPTCs are used for overcurrent protection.
Recommended Devices:
| Device | Key Features | Package | Application |
| SLVU2.8-4 | 2.8V, 4-channel, 2pF, ±15kV Air, ±8kV Contact, IPP:24A | SOP-8 | Gigabit Ethernet ESD protection |
| SG3D05B090 | 90V, Bidirectional, 1.5pF, 5kA | 5mm GDT | Ethernet lightning protection |
| SMD1812-014 | 60V, 0.14A, 0.65Ω | SMD1812 | Interface overcurrent protection |
- Audio and Microphone Interface Protection
Some smart cameras integrate two-way voice functionality; audio and microphone interfaces need to be protected against damage caused by static electricity from the human body.
Design Requirements:
- Low junction capacitance to avoid affecting audio signals
- Fast-response ESD protection
- Miniaturized package
Recommended Devices:
| Device | Key Features | Package | Application |
| SE23T35B5.0MA | 5V, Bidirectional, 0.8pF, ±15kV Air, ±8kV Contact | SOT-23 | Audio interface protection |
| SE10F10B5.0MA | 5V, 0.25pF, ±15kV, 4A | DFN1006 | Microphone interface protection |
- SD Card and Storage Interface Protection
SD card interfaces are typically directly exposed to the user's operating environment, making them susceptible to ESD shocks during insertion and removal.
Recommended Use:
- Ultra-low capacitance ESD protection devices
- Multi-channel array protection solutions
Recommended Devices:
| Device | Key Features | Package | Application |
| SE63T10U5.0LD1 | 5V, 5-channel, 0.5pF, ±25kV Air | SOT-363 | SD card ESD protection |
- Sensor and Control I/O Interface Protection
Security cameras typically connect to sensors and external control interfaces. Although these low-speed signal interfaces have lower data rates, they are still susceptible to ESD damage.
Recommended Devices:
| Device | Key Features | Package | Application |
| SE10F10B5.0A | 5V, Bidirectional, 15pF, ±25kV, 8A | DFN1006 | Sensor power and GPIO protection |
- Power Input Interface Protection
DC12V power supply is the most common power supply method for security cameras.
Power supply requires special protection against:
- Lightning surges
- Power supply overvoltage
- Hot-swap shocks
Recommended Devices:
| Device | Key Features | Package | Application |
| SMCJ15CA | 15V, 1500W, 61.5A | SMC | DC12V surge protection |
| SMDJ15CA | 15V, 3000W, 123A | SMC | High-level surge protection |
| BZT52B5V1 | 5.1V, 500mW | SOD-123 | AC/DC protection |
Summary
Deploying appropriate protection devices at power supply, network communication, audio, storage, and sensor interfaces can effectively reduce the risk of transient overvoltages and improve system reliability.
Semiware offers complete solutions for TVS diodes, ESD protection devices, GDTs, and PPTC protection, helping engineers build stable and reliable security monitoring systems.
👉 Contact Semiware for customized protection solutions for security camera and surveillance applications.
