Design of electrostatic discharge of PCB plate and the solutions
In the design of PCB board, can be layered, proper layout and installation of anti ESD design and implementation of PCB. By adjusting the PCB layout, can be very good to prevent ESD. * multilayer PCB is used as far as possible, the double PCB, the ground plane and power plane, and closely spaced signal earth line spacing can reduce common mode impedance and inductance coupling, so as to achieve the double PCB 1/10 to 1/100. For the top and bottom surfaces are components, with a short connecting line. From the human body, the environment and internal electronic equipment for semiconductor chip precision electrostatic will cause damage, such as through the components inside the thin insulating layer; a gate MOSFET lesion and CMOS components; CMOS device triggers lock; short PN junction reverse biased; short road to biased PN junction; active devices within the melting welding wire or wire. In order to eliminate the electrostatic discharge (ESD) interference and damage to the electronic equipment, need to take a variety of technical means of prevention. In the design of PCB board, can be layered, proper layout and installation of anti ESD design and implementation of PCB. In the des...
Electromagnetic compatibility design of power meter and the solving methods
Compared with the electric parameters of transmitter power industry monitoring instruments commonly used with the traditional, gradually to the intelligent, integrated, multi-functional direction, and in the electromagnetic compatibility requirements are also high performance (EMS and EMI test were related requirements). The designer how to choose appropriate EMC design, a decisive role on the success or failure of the product design. This paper discussed the design of electromagnetic compatibility of the power monitoring instrument. The standard interpretation of 1 standard Combined with the general standard of heavy industrial products, electric power monitoring instrument for power to meet the needs of EMS, EMI and grade is shown in figure 1. 2 standard interpretation Interference is usually divided into two kinds of interference and transient interference. Such as mobile phone, walkie talkie, radio signal to interference. Because the switch, motor braking power fluctuation caused by such interference, we called the transient interference. Contains the transient interference figure 1: surge SURGE, static ESD, electrical fast transient EFT/B, voltage dips, short interruptions...
For the solution of electrostatic discharge problems
For the solution of electrostatic discharge problems, according to the following twelve rules to (prioritize) 1.PCB non insulated casing wire and other wire distance of at least 2.2 mm. This applies to all objects connected to the chassis ground, including trajectory. 2 chassis wire length should not be more than five times its width. Metal objects 3 the circuit without insulation and the operator can touch to the PCB area or ungrounded separated by at least 2 cm. 4 power line and ground wire or ranking on PCB and in the same layer, or placed adjacent to the two layer. 5 the ground plane and ground wire must be connected to the network. In an arbitrary direction, at least 6 cm every connection a vertical line and horizontal line. Especially the double PCB plate, that is to say, the first layer PCB board layout can be ground level, and the second layer can be vertical ground, must be at least every 6 centimeters place a hole has been connected to both (of course, less than 6 cm in the local connection is better than the ground grid, ground plane. ) 6 of all signal lines must be in the ground plane edges or less than 13 mm above the ground. Wire can be distributed in the same la...