A Detail Introduction Of PCB

The circuit board has become an important part of today's electronic products. With the development of electronic technology and PCB manufacturing technology, modern electronic products are becoming more and more complicated, and the density of printed circuit boards is increasing. Testing and repair is also more difficult. In order to improve the detection of printed circuit board and maintenance of the degree of automation, the design of the circuit board automatic test system is very necessary.

At present, the rapid development of printed circuit board automatic test technology, printed circuit board online test system (ATE) is widely used in printed circuit board and a variety of products printed circuit board production, testing and maintenance links. As the user's test requirements, the test object is different, its specific performance (or function), test principles and test methods are also different, it needs tailored, a single custom to meet the user's requirements, and the system is less common , Resource reusability is low. In view of the above situation, this article designed a more common automatic test system, used to test whether the circuit board is working properly, to achieve a variety of circuit board on-line testing.

The main chips used in this system are: the main chip EP2S63, AD sampling chip AD7864 and AT84AD331. The following three kinds of chips for a brief introduction:

EP2S63 is ALTERA's Strati series of FPGAs, which use advanced 93 nm production technology; the FPGA performance to a new height, the industry is the industry's fastest, highest density FPGA. The EP2S63 has up to 84 dedicated LVDS differential logic receive chaels, each with a data transfer rate of up to 1 Gb / s. Its internal high-speed digital phase-locked loop circuit, can produce for the ADC circuit using the clock signal.You may be familiar with attiny85 date sheet, of course, there are many electronic component distributors to supply it.

The AD7864 is a low-speed, low-power, 4-chael simultaneous 12b A / D converter. It has a 12-bit A / D converter that can sample up to four input chaels and has four samples to hold the amplifier; a single supply (+5 V), multiple conversion voltage ranges, for each analog input chael Overvoltage protection circuit; 4 chaels at the same time work, the maximum sampling rate of 133 kHz.

AT84AD331 is Atmel's high-speed acquisition chip. The device integrates two (I and Q) independent ADCs with 8 b conversion accuracy, each chael has a sampling rate of l Gs / s, and a sampling rate of 2 Gs / s in interleaved mode. The chip is based on the requirements of high-speed applications, analog input, digital clock input, digital clock output, data output, synchronous clock output are used in differential mode. Data output using LVDS standard, the transfer rate of up to 1 Gb / s, the use of its internal multi-demultiplexer, can reduce the output data rate, can also be easily coected with many types of high-speed FPGA directly.

AT84AD331 can be configured as I and Q road alone, this time can simultaneously collect two signals, the maximum sampling rate of 1 Gs / s; can also be configured to I and Q road staggered sampling, this time can only collect a signal , The equivalent sampling rate of 2 Gs / s, when used in accordance with the need for the chip on-line configuration.

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