ICT test for PCBA, In—Circuit—Tester, common PCBA test method, PCBA processing, Common ICT test methods, PCBA board, China PCBA manufacturer, Shenzhen PCBA manufacturer
What is ICT test for PCBA?

The full name of ICT is In—Circuit—Tester, it is a common PCBA test method in PCBA processing.

The ICT test mainly detects faults such as short circuits, open circuits, and component soldering by contacting test points on the PCBA board with test probes. Capable of quantitatively measuring resistance, capacitance, inductance, crystal and other components, functional tests on diodes, triodes, optical amplifiers, transformers, relays, operational amplifiers, power modules, etc., and functional tests on small and medium-sized integrated circuits, such as 74 series, memory class, common driver class, exchange class IC.

Common ICT test methods

1. Analog device test

Test with operational amplifers. The concepts of "virtual ground" from point "A" are:

  ∵Ix = Iref
  ∴Rx = Vs/ V0*Rref

Vs and Rref are the excitation signal source and the instrument's calculated resistance, respectively. Measure V0, then Rx can be found. If the Rx to be measured is a capacitor or an inductor, the Vs AC signal source and Rx are in the form of impedance, and C or L can also be obtained.

2. Vector test

For digital ICs, the Vector test is used. The vector test is similar to the truth table measurement, stimulating the input vector, measuring the output vector, and judging the quality of the device through the actual logic function test. Example: NAND gate test.

For the test of analog IC, the voltage and current can be stimulated according to the actual function of the IC, and the corresponding output can be measured as a function block test.

3. Non-vector testing

With the development of modern manufacturing technology and the use of very large-scale integrated circuits, it often takes a lot of time to write a vector test program for the device. For example, the test program of the 80386 requires a skilled programmer for nearly half a year. The large number of applications of SMT devices has made the open pin fault phenomenon more prominent. To this end, various companies launched the non-vector testing technology, for example, Teradyne launched MultiScan, GenRad launched Xpress non-vector testing technology.

ICT testing is at the back end of the PCBA production process but it is the first process of PCBA testing, can timely discover problems in the PCBA board production process, which helps to improve the process and increase the production efficiency.