PCB Technical - Precautions for smart bracelet PCB copy board

PCB designers must make products in time. In such a fast-paced environment, product planning and implementation are extremely important, and implementation issues must be actively addressed.

A smart bracelet usually consists of a radio frequency circuit unit, a clock circuit unit, a memory circuit unit, a sensor circuit unit, and a master MCU unit. The circuit PCB is usually concentrated in a small area for single-sided or double-sided patching. The circuit board copy board is mainly 4 or 6 layers. The picture below shows the circuit PCB of a smart bracelet reversely disassembled by Longwin Technology.

Since so many functions are concentrated on a small PCB board, we need to pay special attention to the layout and wiring of the bracelet. Now we summarize some precautions for reference.

First of all, the partition layout, pay attention to the wiring protection.

It can be seen from the PCB circuit board above that the various parts of the smart bracelet circuit (marked with different color boxes) are well partitioned: because the smart bracelet is a collection of digital circuit components, just do it in the PCB copy board A good matching resistance and capacitance distribution can complete a circuit module with a certain function, which makes the PCB copy board more concise and easy to find. Although some sensor circuit units use analog circuit technology for data collection, once the module is designed as a module, data communication and information transmission can be completed through the corresponding connection interface.

In the layout of circuit modules, on the one hand, it is necessary to pay attention to the shortest path between the clock circuit and the crystal oscillator circuit to reach the target control. On the other hand, pay attention to avoiding the data line when the clock is routed to prevent interference from affecting the stability of the system.

When wiring, it is necessary to protect the key wiring, such as whether the clock generation circuit, crystal oscillator circuit, etc. are protected by copper, whether the ring ground protection is performed, etc., generally will be protected in the design, and the crystal oscillator part needs to be digging copper. .

Secondly, handle the RF PCB circuit well.

The smart bracelet needs to be linked with the mobile phone when in use. Therefore, the radio frequency part is the key part. In this part of the design, special attention must be paid. Now the smart bracelets on the market are nothing more than wireless data transmission based on Bluetooth, so the focus is on the processing of Bluetooth radio frequency. If the smart bracelet is only used for data transmission and does not require the transmission of sound and music, then Bluetooth Low Energy is the best choice. In the design, the shape of the Bluetooth antenna, the antenna layout, and the material of the smart bracelet casing all affect the intelligence An important factor in the performance of the bracelet. In the process of copying the PCB of the smart bracelet, an excellent RF antenna engineer is particularly important.