Overview
Sensors are ubiquitous in modern industry, automotive electronics, medical equipment, and various smart devices. They measure temperature, pressure, light, motion, and even vital signs, providing critical data for systems. However, sensor circuits are easily damaged by abnormal external voltages.
You might think, "Sensors are just for collecting data, right? Won't abnormal voltage damage them?" The answer is yes. Static electricity in factory workshops, voltage fluctuations in automotive electronic systems, or surge voltages during thunderstorms can all instantly damage sensor circuits. Without protection, not only may the equipment be damaged, but the data will also be distorted, potentially leading to system shutdown or even a safety accident.
So, how can we provide robust protection for sensors? We can start with the interface and provide targeted protection solutions for different types of signals:
1️⃣ Coaxial Interface
For coaxial interfaces requiring high-speed signal transmission, we recommend using a combination of an SG4532B090 gas discharge diode (GDT) and a GBLC05CI ESD diode.
- SG4532B090: 90V, 2kA surge protection capability, shunts energy during instantaneous voltage surges to protect downstream circuits.
- GBLC05CI: 5V, ±30kV ESD protection, with a capacitance of only 1.5pF, which does not affect signal transmission speed.
SG4532B090 ↗️ https://en.semiware.com/gas-discharge-tubes/sg4532b090/
GBLC05CI ↗️ https://en.semiware.com/esd-diodes/gblc05ci/
2️⃣ RS485 / RS232 Interface
RS485/RS232 interfaces are commonly used in industrial automation and communication equipment. These interfaces operate at low voltages but are frequently exposed to electrostatic discharge (ESD) risks in long-haul environments.
The SM712 ESD diode (±25kV, SOT-23) provides reliable protection, effectively absorbing external ESD and ensuring stable, uninterrupted communication.
SM712 ↗️ https://en.semiware.com/esd-diodes/sm712/
3️⃣ CAN Bus
The CAN bus is crucial in automotive electronics and industrial equipment, handling high-speed data exchange.
The SE23T20B24LB ESD diode (SOT-23, 24V, ±20kV, 13pF) not only provides ESD protection but also withstands small surges, ensuring smooth and error-free bus data transmission.
SE23T20B24LB ↗️ https://en.semiware.com/esd-diodes/se23t20b24lb
4️⃣ USB Interface
USB interfaces are ubiquitous, but they are also a high-risk area for ESD and surges.
The SR05 ESD diode (SOT-143, 5V, ±20kV, 2pF) provides a low-capacitance, high-protection solution that protects the interface without affecting high-speed data transmission.
SR05 ↗️ https://en.semiware.com/esd-diodes/sr05/
Sensor Circuit Protection Scheme Diagram

Conclusion
Sensors, though small, carry critical data. Whether in industrial plants, automotive electronics, medical equipment, or outdoor smart devices, equipping sensors with "voltage protection armor" ensures long-term stable operation.
Choose more reliable sensor protection, starting with Semiware. Visit our website today for professional ESD/surge protection solutions and more product application references. 👉 https://en.semiware.com/applications/sensor/


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