Electrostatic and surge protection solutions for electrocardiographs
Overview
As a precision medical electronic device, the ECG monitor transmits data via WiFi, Bluetooth, and NFC, so its stability and security are of vital importance. During design and use, the impact of electromagnetic interference such as electrostatic discharge and surge on its performance and safety must be considered.
Reference standards
Main sources of static electricity and surge
1. Sources of static electricity
2. Sources of surges
Application Block Diagram
Solution description and recommended protection devices
1. AC-DC power input port
In electrocardiographs or other precision electronic equipment, the surge protection design of the AC-DC power input port is crucial. It is the first line of defense to prevent transient high voltage damage to the equipment caused by lightning strikes, power grid fluctuations, and plugging and unplugging.
It is recommended to use the circuit protection product combination of SG2R08B600A ceramic gas discharge tube and 14D561K varistor.
The SG2R08B600A gas discharge tube adopts a surface mount package shape, with low inter-electrode capacitance, strong surge absorption ability, low insertion loss, and long service life. It is widely used in electrical and communication equipment to provide transient overvoltage protection, especially for ADSL, communication base stations, communication power supplies, photovoltaics, energy storage and other industries. The core electrical parameters are as follows. For more product details, please visit: https://en.semiware.com/power-gas-discharge/sg2r08b600a/
14D561K Varistor, high surge current, radial leaded varistor can provide an ideal circuit solution for low voltage DC voltage applications, providing higher rated voltage and maximum peak surge current than before in these small chips to prevent high peak surges, including indirect lightning interference, system switching transients from power supply and abnormal fast transients. The core parameters are as follows. For more product details, please visit: https://en.semiware.com/product-general-mov/14d561k/
2. Battery charging port
Designing electrostatic discharge (ESD) protection for the battery charging interface is an important measure to ensure the reliability of the charging circuit and extend the battery life.
It is recommended to use the SE10F55U4.5A series of electrostatic suppressor products, which adopt the DFN1006-2L standard package. It has the characteristics of small leakage current, fast response speed (nS level), high reliability, etc. It is widely used in ESD electrostatic protection of high-speed signal transmission interfaces such as HDMI, USB, VGA, etc., protecting each input/output pin and providing high-level protection for electronic devices that may experience destructive electrostatic discharge (ESD). The core parameters are as follows. For more product details, please visit: https://en.semiware.com/tvs-array/se10f55u4-5a/
3. DC-DC Power Supply
In the design of DC-DC power supply modules, although surge protection is not as violent as AC input, it is still very critical in sensitive or high-reliability applications such as industry, electric vehicles, and medical treatment.
It is recommended to use the SVB60B6.0 series high-reliability TVS diodes. Through advanced packaging technology, it adopts surface-mount SMB standard packaging, with a rated power of 600W, extremely fast response time (sub-nanosecond level) and a fairly high surge absorption capacity. It is specially used to protect sensitive electronic equipment in circuit applications from transient voltages caused by lightning strikes and other transient voltage events. The core parameters are as follows. For more product details, please visit: https://en.semiware.com/product-tvs-diode/svb60b6-0/
4. RJ45 interface
RJ45 interface (Ethernet port) is a communication interface that is frequently plugged and unplugged, exposed to the outside, and connected to long cables. It is very susceptible to electrostatic discharge (ESD) and surge interference. Especially in industrial equipment, medical equipment, cameras, routers and other occasions, good electrostatic protection design is the key to ensure stable operation of the interface and avoid equipment damage.
It is recommended to use the GDT-SG4532B090 ceramic gas discharge tube, ESD-SE3D35B3.3MA electrostatic suppressor and PTC-SK250-145 self-recovery fuse product combination for protection.
SG4532B090 ceramic gas discharge tube, using 4.5×3.2×2.7mm micro-chip package, has the characteristics of low inter-electrode capacitance, strong surge absorption capacity, low insertion loss, long service life, etc., and is particularly suitable for use in the field of ECG oscilloscopes. The core parameters are as follows. For more product details, please visit: https://en.semiware.com/power-gas-discharge/sg4532b090/
The SE3D35B3.3MA electrostatic suppressor adopts SOD-323 standard package, with small leakage current, fast response speed (nS level), high reliability and other characteristics. It is widely used in ESD electrostatic protection of high-speed signal transmission interfaces such as HDMI, USB, and VGA. The core parameters are as follows. For more product details, please visit: https://en.semiware.com/tvs-array/se3d35b3-3ma/
SK250-145 resettable fuse adopts a plug-in appearance structure. The product has the physical characteristics of self-recovery and is widely used in overcurrent protection in consumer electronics, computers, lighting, instruments and other industries. The core parameters are as follows. For more product details, please visit: https://en.semiware.com/product-pptc/sk250-145/
5. RS485/RS232 interface
The RS-485/232 interface is a commonly used communication method in electrocardiographs (or other medical electronic equipment), especially for remote data transmission (such as communication with host computers and monitoring systems). Since the RS-485 interface is often extended through external connecting lines and exposed to the human body or medical environment, it is very susceptible to interference or even damage from electrostatic discharge (ESD), lightning-induced surge (Surge), and fast transient pulses (EFT).
It is recommended to use a product combination of SG3D05B090 ceramic gas discharge tube, SVB60B15 high-reliability TVS diode, SE23T40B712B multi-channel electrostatic suppressor and STB100B6.0 semiconductor discharge tube for surge and electrostatic protection.
The SG3D05B090 gas discharge tube adopts a surface mount package shape, with low inter-electrode capacitance, strong surge absorption capacity, low insertion loss, and long service life, which is very suitable for use in RS-485/232 interface. The core parameters are as follows. For more product details, please visit: https://en.semiware.com/power-gas-discharge/sg3d05b090/
SVB60B15 high-reliability TVS diode products, through advanced packaging technology, use surface mount SMB standard packaging, rated power 600W, with extremely fast response time (sub-nanosecond level) and quite high surge absorption capacity. The core parameters are as follows. For more product details, please visit: https://en.semiware.com/product-tvs-diode/svb60b15/
The SE23T40B712B multi-channel electrostatic suppressor adopts the SOT-23 standard package and a bidirectional asymmetric voltage design. It has the characteristics of low leakage current, fast response speed (nS level), and high reliability. The core parameters are as follows. For more product details, please visit: https://en.semiware.com/tvs-array/se23t40b712b/
The STB100B6.0 semiconductor discharge tube product uses Semiware's unique process technology and SMB standard packaging. While meeting customers' large surge suppression needs, it reduces the product size and is widely used in the field of video surveillance. The core parameters are as follows. For more product details, please visit: https://en.semiware.com/high-reliability-thy/stb100b6-0/
6. USB Interface
The USB interface in the electrocardiograph is a key data interaction and/or charging interface. It is also the most likely entry point for problems such as electrostatic discharge (ESD), overvoltage, surge, and electromagnetic interference (EMI). Considering the high requirements of medical equipment for reliability, patient safety, and electromagnetic compatibility (EMC), electrical protection of the USB interface is particularly important.
It is recommended to use the SE41T06U5.0LB series multi-channel electrostatic suppressor, which adopts the SOT-143 standard package and has the characteristics of small leakage current, fast response speed (nS level), and high reliability. The core parameters are as follows. For more product details, please visit: https://en.semiware.com/tvs-array/se41t06u5-0lb/
Learn more
For more detailed information on this solution, please contact our engineering team or visit the specific reference design page: https://en.semiware.com/applications/ecg-monitor/; during the design process, you can also provide more information (such as operating voltage, interface type, whether it is grounded, etc.), and we can design the solution and build the test environment according to your requirements.
About Semiware
Semiware is a comprehensive service provider of circuit protection solutions. The company relies on its technology in the semiconductor field and the application background of terminal products to serve customers in the electronics, automotive and industrial markets. We have a rich portfolio of circuit protection devices to meet customer needs, including overvoltage protection, overcurrent protection, composite protection, discrete devices and advanced packaging technology. We provide customers with complete solutions and product portfolios through EMC laboratories and FAE engineers around the world. For more information, please visit https://en.semiware.com