ICT test
In the ICT test, the test probe is mainly contacted with the test points on the PCBA board, and faults such as short circuit, open circuit and component soldering of the line can be detected. It can quantitatively measure devices such as resistors, capacitors, inductors, crystal oscillators, etc., and perform functional tests on diodes, transistors, transistors, transformers, relays, operational amplifiers, power modules, etc., and perform functional tests on small and medium-sized integrated circuits, such as all 74 series, Memory class, common driver class, switching class and other ICs.
Some methods of ICT testing are available;
1, analog device testing
Test with an operational amplifier. The concept of "virtual land" from "A" point is:
∵Ix = Iref
∴Rx = Vs/ V0*Rref
Vs and Rref are respectively the excitation signal source and the instrument calculation resistance. When V0 is measured, Rx can be found. If the Rx to be tested is a capacitor or an inductor, then the Vs AC signal source and Rx are in the form of impedance, and C or L can also be obtained.
2, Vector (vector) test
For digital ICs, the Vector test is used. The vector test is similar to the truth table measurement, the excitation input vector, the measurement output vector, and the actual logic function test to judge whether the device is good or bad. Such as: NAND test
For the test of the analog IC, the voltage and current can be excited according to the actual function of the IC, and the corresponding output can be measured as a function block test.
3, non-vector test
With the development of modern manufacturing technology and the use of very large scale integrated circuits, vector test programs for writing devices often take a lot of time. For example, the 80386 test program takes a skilled programmer for nearly half a year. The large number of applications of SMT devices has made the phenomenon of open circuit pins more prominent. For this company's non-vector testing technology, Teradyne introduced MultiScan; GenRad's Xpress non-vector testing technology.
The ICT test is at the back end of the production process. The first process of the PCBA test can promptly discover the problems of the PCBA board production process, which helps to improve the process and improve the production efficiency.
date：2019-04-30 17:45:00
Building 1, Senyang Electronic Technology Park, Guangming High-tech Park, Yutang Street, Guangming District, Shenzhen City.
F:86-13418481618
pcba13@fastpcba.cn
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