Everyone knows that it is a PCB board that turns the designed schematic into a real PCB board. Please don't underestimate the process. There are many things that work well in the project but it is difficult to achieve in the project, or Something else that others can achieve can't be realized, so it is not difficult to say that it is a PCB board, but it is not an easy task to make a PCB board.
The two major difficulties in the field of microelectronics are the processing of high-frequency signals and weak signals. In this respect, the level of PCB production is particularly important. The same principle design, the same components, different PCBs produced by different people have different results. So how can I make a good PCB? Based on our past experience, I would like to talk about my views on the following aspects:
First, we must clearly define the design goals
To receive a design task, we must first clarify its design goals. It is an ordinary PCB board, a high-frequency PCB board, a small signal processing PCB board, or a PCB board with both high frequency and small signal processing. If it is an ordinary PCB board, As long as the layout and wiring are reasonable and tidy, the mechanical dimensions can be accurate. If there are medium load lines and long lines, it must be processed by certain means to reduce the load. The long line should be strengthened, and the focus is to prevent long-line reflection.
When there are more than 40MHz signal lines on the board, special consideration should be given to these signal lines, such as crosstalk between lines. If the frequency is higher, there is a stricter limit on the length of the wiring. According to the network theory of the distributed parameters, the interaction between the high-speed circuit and its connection is a decisive factor, which cannot be ignored in the system design. As the transmission speed of the gate increases, the opposition on the signal line will increase accordingly, and the crosstalk between adjacent signal lines will increase proportionally. Generally, the power consumption and heat dissipation of the high-speed circuit are also large. Should be given enough attention.
When there are weak signals of millivolts or even microvolts on the board, special attention should be paid to these signal lines. Because the small signals are too weak, they are very susceptible to interference from other strong signals. Shielding measures are often necessary, otherwise Greatly reduce the signal to noise ratio. As a result, the useful signal is overwhelmed by noise and cannot be extracted efficiently.
The commissioning of the board should also be considered in the design stage. The physical location of the test points and the isolation of the test points cannot be ignored, because some small signals and high-frequency signals cannot be directly added to the probe for measurement.
In addition, other related factors should be considered, such as the number of layers of the board, the package shape of the components, and the mechanical strength of the board. Before making a PCB board, it is important to make a design goal for the design.
Second, understand the function of the components used, the layout and wiring requirements
We know that some special components have special requirements in place and route, such as analog signal amplifiers used in LOTI and APH. Analog signal amplifiers require stable power supply and low ripple. The analog small signal portion should be as far away as possible from the power device. On the OTI board, the small signal amplification section is also specially equipped with a shield to shield stray electromagnetic interference. The GLINK chip used on the NTOI board adopts the ECL process, and the power consumption is large and the heat is very strong. The heat dissipation problem must be specially considered in the layout. If natural heat dissipation is used, the GLINK chip should be placed in a place where the air circulation is relatively smooth. And the heat that is dissipated cannot make a big impact on other chips. If a horn or other high-powered device is mounted on the board, it may cause serious pollution to the power supply, which should also be paid enough attention.
Third, the consideration of component layout
One of the first considerations for the layout of components is the electrical performance. The components with close wiring are put together as much as possible, especially for some high-speed lines. The layout should be as short as possible, power signals and small-signal devices. To be separated. Under the premise of satisfying the performance of the circuit, it is also necessary to consider that the components are placed neatly and beautifully, and it is easy to test. The mechanical size of the board and the position of the socket need to be carefully considered.
Grounding and transmission delay times on high-speed systems are also the first considerations in system design. The transmission time on the signal line has a great influence on the total system speed, especially for high-speed ECL circuits. Although the speed of the integrated circuit block itself is very high, due to the common interconnection line on the bottom plate (about 30cm line length) The 2 ns delay amount) causes an increase in delay time, which can greatly reduce the system speed. Like the shift register, the synchronous counter is preferably placed on the same board, because the delay time of the clock signal to different boards is not equal, which may cause the shift register to be wrong. On a board, where synchronization is critical, the length of the clock lines connected from the common clock source to each board must be equal.
High PFC Junction Box Led Driver(UL Cert.)
A High PFC and rugged Iron enclosure that complies with electrical codes requiring junction boxes to separate household and low voltage wiring.
With the increasing demands for safety levels, and then the North American market does not allow the wiring to be exposed, so the production of Junction box led driver.High security level, with short circuit protection, but also do dimming and non-dimming led driver.
Features & Benefits
- UL Listed
- Powder-coated iron
- High PFC
- Lightweight
Details
The HN-Junction Box is a high PFC, rugged iron enclosure designed for use with our Constant Current Drivers. This junction box is a NEMA 1 rated indoor enclosure made of lightweight but strong iron with a protective black powder-coated finish. Designed for contractor installation, this junction box is ULListed and features separation for low-voltage and high-voltage wiring in an electrical enclosure. It features four 0.20 inch mounting holes for surface mounting and is designed with mounting hole positions to hold compatible power supplies securely.The HN-Junction Box is for use with the following Constant Current Drivers only:
- 1) 100-347Vac 25-42Vdc 1300mA
- 2) 100-347Vac 25-42Vdc 1100mA
- 3) 100-277Vac 25-40Vdc 1500mA
- 4) 100-277Vac 25-40Vdc 2000mA
Product Specs
Output voltage:25-40V
Output wattage: 45W
Dimensions:188x86x33 mm
Efficiency:88%
Encironment/IP Rating: indoor/IP20
Max. Input voltage:277V
Dimming way: 0-10V/PWM/RX
Certificate: UL, FCC, Class P
Junction Box Led Driver
Ul Standard Led Driver,Led Panel Light Junction Box,Led Panel Light Driver
ShenZhen Fahold Electronic Limited , https://www.fahold.com