PCB News - Brief Analysis of EMC Design of Iphone6

I believe you have seen the dismantling diagrams of many manufacturers' machines. But looking at the inside, there are basically no foam, conductive cloth, etc. Is it because the PCB board is well designed without stray interference and other issues? Think about it and know it's impossible. So Apple's products are expensive, indeed because of its well-done. In addition, while solving the EMC problem, it also ensures the beauty of the interior. This is really not easy.

1. The position of the connector here is that metal is added to the top of the connector, which increases the mechanical strength of the interface and also enhances the grounding performance.

2. Below is the interface (red) under the protection of the metal parts. Conductive foam is adhered to it to enhance the contact with the metal cover. Everyone knows that there are more strays at the interface. Inside the blue box is the conductive cloth on the shield.

Looking at the picture below, not all connectors have foam added, so these foams are added according to actual needs.

3. Did you see it? All connectors are available, and being rich is self-willed. In addition, many of our FPCs are dark yellow or orange. Do you see the green box? It is basically certain that the FPC has shielding layers on the upper and lower layers. The black outermost layer is insulating. This kind of FPC is relatively hard, and everyone who has been disassembled must know it.

4. I won't talk about the red part. There is no black conductive cloth on the shield cover in the green frame. It's beautiful, isn't it? Shield covers in other locations are also available.

5. A large piece of metal. There is nothing to say about this. Everyone knows what the red part is. All the interfaces and FPC are protected, too lazy to talk about it.

6. The position of 1 is to strengthen the ground contact with the shell. The position of 3 is still the connector. 2 is FPC. Each performs its duties and covers everything. However, there may be some measures that I have not noticed or understood. I don’t know if the surrounding black is dustproof, waterproof or conductive adhesive. The first two are more likely.

7. Suppliers also have to follow Apple's standards and take a look. The shielding layer of the FPC reaches to the side of the camera connector. You should be able to see it clearly in the picture.

8. Have you seen it? A small RF connector has been strengthened for grounding. Have you seen the second one? (What, have you seen it? Didn’t you come to smash the place? Just go cool)

9. Do you see the slot of the camera?

10. Find a relatively complete picture and fill it up for everyone. In addition, the four contacts inside the red circle are also grounded. The camera of the product I made is put directly in the slot, and there is no shrapnel contact. However, there is also a possibility that the camera technology requires extremely accurate camera position for optical image stabilization. Here, please confirm with the camera expert. All I can see is the enhanced grounding of the camera housing.

11. Can you see the conductive area on the cavity? But I don’t know why there is no conductive foam to enhance the contact. The upper part is the PCB board, which is in contact with the shielding cover. It may be verified that only the one on the right side needs to be foamed. The ground contact here is enough. Let me say one more thing here. You may ask, why are not all conductive here? Is it afraid of a short circuit? Short circuit is definitely impossible. My opinion is to conduct electricity only in a fixed position, so as to prevent the signal from running out of order, but the spurs are only conducted through a few fixed paths. It's like digging a few ditches, and all the water goes in the ditches, so you only need to find a way to treat the water in the ditches.

12. The button is also a standard. Black, everyone knows it.

13. The motor is still not let off, and there are two ways to ground it. By the way, not all conductive foams are the same. Similarly, conductive cloth is not all the same. The material is good, which supplier is good. Which frequency band corresponds well? There is a lot of knowledge in it. Interested students can go and search to see if it is as simple as it seems. Finally, the area thickness of the conductive foam and the area thickness of the conductive cloth are randomly selected? You say yes? That's how you did it! Well, I can only say that your drawing Tucson is broken.

14. Another overall picture, no explanation.

15. The last picture I want to say is that it is not only conductive foam, conductive cloth, conductive coating and other measures. On the board, Apple will definitely spend a lot of effort to optimize EMC performance. After all, a capacitor is much cheaper than a piece of conductive cloth. For example, some small package capacitors near the power IC and memory chips. Experts should know what they are used for. In addition, there are many similar designs, so I won’t post them one by one. The textures are also very tiring. But everyone does not need to thank me! In addition, I would like to emphasize here that when making layout and wiring, we must also consider a lot of EMC requirements. It's a pity that we can't get the PCB layout, otherwise we can really learn how to deal with some clock lines, radio frequency lines and power lines with relatively large interference apple.

I hope that everyone can learn from Apple's design philosophy of pursuing perfection, and make more refined products as soon as possible.

The above is a brief introduction to EMC design of Iphone6 mobile phone. Ipcb is also provided to PCB manufacturers and PCB manufacturing technology.