ESD Static Electricity Rectification Issues of Micro Medical Products

QWE4562009

ESD Static Electricity Rectification Issues of Micro Medical Products [Copy link]

 

ESD Static Electricity Rectification Issues of Micro Medical Products

There is a medical product similar to the size of a TWS headset/hearing aid (needs to contact the human body), with four metal contacts exposed on the shell. The functions of the four contacts are 4.2V (lithium battery charging), GND, TX (serial communication sending), RX (serial communication receiving); the product has passed the old ESD standard of air discharge ±8KV and contact discharge ±6KV (4.2V, TX, RX are added with ESD electrostatic tubes respectively);

After May 1, 2023, we will have to test according to the new ESD standard of ±15KV air discharge and ±8KV contact discharge. I am worried that it will not pass. I have already obtained the registration certificate and cannot change the existing structure (the board size cannot be changed, and the existing board space can no longer squeeze in a 0402 component); (medical products, and this is a difficult problem according to the existing structure) What good solutions can you share? ? ?

LuJianchang

Is Figure 3 a real thing? It looks like there is still a lot of room for components.

tagetage

1. It seems that there is still a lot of space on the PCB to place components.

2. What brand and model is your original electrostatic tube? Another way is to replace it with the best electrostatic tube in the world, such as Littelfuse.

秦天qintian0303

We can only start with the TVS tube, which itself has little creepage distance.

吾妻思萌

Three anti-paint finish

QWE4562009

LuJianchang posted on 2023-2-7 18:24 Is Figure 3 a real thing? It looks like there are still many places to put the components

No, it's similar to this shape. The actual product PCB is not convenient to take pictures. . . The space is very tight.

QWE4562009

Azuma Simeng published on 2023-2-8 17:39 Let's get started with the three-proof paint~

Do you mean to apply conformal coating to the whole board?

QWE4562009

tagetage posted on 2023-2-7 19:06 1. It seems that there are still many places on the PCB to place components. 2. What brand and model is your original electrostatic tube? Another way is to change...

No, it's similar to this shape. The actual product PCB is not convenient to take pictures. . . The space is very tight.

QWE4562009

tagetage posted on 2023-2-7 19:06 1. It seems that there are still many places on the PCB to place components. 2. What brand and model is your original electrostatic tube? Another way is to change...

I used to use Uni-Eng. By the way, when choosing a model, are the withstand voltage and maximum current the main considerations? ESD

QWE4562009

LuJianchang posted on 2023-2-7 18:24 Is Figure 3 a real thing? It looks like there are still many places to put the components

No, it's similar to this shape. The actual product PCB is not convenient to take pictures. . . The space is very tight.

QWE4562009

tagetage posted on 2023-2-7 19:06 1. It seems that there are still many places on the PCB to place components. 2. What brand and model is your original electrostatic tube? Another way is to change...

Littelfuse brand. Is this a foreign brand?

QWE4562009

tagetage posted on 2023-2-7 19:06 1. It seems that there are still many places on the PCB to place components. 2. What brand and model is your original electrostatic tube? Another way is to change...

I see that many domestic products are better than Litte in terms of pressure resistance. I wonder if there is any false labeling.

tagetage

Littelfuse is the world's #1 brand of circuit protection.

tagetage

Infineon Technologies Nexperia SEMTECH Vishay Littelfuse BrightKing Amazing STMicroelectronics ON Semiconductor WAYON Diodes Inc. Bourns LAN technology ANOVA MDE Toshiba Uni Semiconductor PROTEK INPAQ EIC SOCAY

Most circuit protection manufacturers are listed above. You can choose according to your needs. I would definitely choose a big foreign brand.

吾妻思萌

QWE4562009 posted on 2023-2-8 18:04 Do you mean to apply conformal coating to the whole board?

It would be much better if you spray the entire board.

QWE4562009

Azuma Simeng posted on 2023-2-8 21:47 If you have spray paint, spray the entire board and it will be much better.

Are all components also sprayed?

吾妻思萌

QWE4562009 posted on 2023-2-9 16:56 Are all components also sprayed?

Except for the reserved connector part, the rest of the parts can be sprayed evenly to prevent short circuit and dirt.

QWE4562009

Azuma Simeng published on 2023-2-9 19:33 Except for the reserved connector part, the rest can be sprayed evenly to prevent short circuit and dirt

Many people suggest that the entire board should be coated with conformal coating. Will it help pass ESD?

吾妻思萌

Azuma Simeng published on 2023-2-9 19:33 Except for the reserved connector part, the rest of the parts can be sprayed evenly to prevent short circuits and dirt

Many people suggest that the entire board should be filled with three-proof paint. Will it help pass ESD?

Some esd is electrostatic discharge. As I understand it, esd involves a lot of metaphysics (I am not very good at it). Humidity, temperature, friction, contact, junction, capacitance, static electricity accumulation... There are many concepts~ I can't explain them clearly. I only know that the watch board of Apple has a three-proof coating~

QWE4562009

Azuma Simeng posted on 2023-2-10 16:40 Many people suggest that the entire board should be filled with three-proof paint. Will it help pass ESD? [/quote] Some esd is electrostatic discharge. I...

Is there a nano coating that is better than three-proof paint?