PCB LAYOUT engineers also need to understand the ICT Flying Probe test

 As a PCB LAYOUT engineers must understand the ICT Flying Probe test, so it was clear the significance of the test points in the PCB design process. Many companies require ICT test points should be added to more than 95%, PCB design is very difficult, do all of the PCB LAYOUT, often add test points to spend the day.
Flying Probe ICT only basic static test, the advantage is that without production fixture and program development time is short. ICT offers the potential of the needle bed type Analog Devices features and digital devices logic function test, high fault coverage, but each veneer need to create a dedicated bed-of-nails fixture, jig making and program development cycle.
 Online test of ICT, In-Circuit Test, online components, electrical properties and electrical connection test to check for manufacturing defects and adverse components of a standard test methods. Online test in the "circuit the tester referred to of ICT (In-Circuit Test System), the Chinese customary called the online test is mainly used for the test board assembly (PCBA). "Online" is the literal translation of "In-circuit, mainly referring to the electronic components on the line (or circuit). Online testing is a continuous open circuit, do not remove the component pin testing technology, "online" to reflect ICT focuses on the circuit board assembly components on-line on the road or open short-circuit state test to detect.
 Open short circuit test circuit board, resistors, capacitors, inductors, diodes, transistors, transistors, IC and other components! Check online single components as well as open, short circuit of the circuit network is simple, quick and rapid, accurate fault location.
Early industry ATE equipment is also classified in this category of ICT, but ATE test is relatively complex, but also includes a power-on functional testing, like the TTL, the OPAMP, Frequency, and the TREE, BSCAN, MEMORY, so the ATE independent of the other categories!
Basically where large circuit manufacturers to be used in the ICT test, like ASUS, DELL, IBM, INTEL, BENQ, MSI, HP and other!
The world's largest ICT test equipment manufacturers as Agilent, there are other Teradyne, Aveda the T2000, Galaxia, Ying Qi (WINCHY) and other.
By poor manufacturing defects and components on the device electrical performance test. Component class can check out the component values ​​of tolerance, failure or damage to the Memory class of procedural errors. Process class can be found a short circuit, such as solder element inserted in the wrong plug anti-leakage loaded pins tilt, cold solder joint, PCB short circuit, break failure.
 Examination made of the electrical performance of panel line components and circuit network connection. Able to quantitatively measure resistors, capacitors, inductors, crystals and other devices, diodes, transistors, optical coupling, transformers, relays, operational amplifiers, power supply module and other functional testing, functional testing of small and medium-scale integrated circuits, As with all 74 series, the Memory, common drive class, exchange such as IC.
Test failures directly targeted at the specific components, the device pins, the network points, fault location is accurate. Fault repairs do not need more expertise. Process control, automated testing, operation is simple, fast and rapid test, the veneer of the test time is generally in a few seconds to tens.
The online test is usually the first test in the production process, a timely response to the manufacturing conditions conducive to process improvement and upgrading. ICT test failure of the board, due to the fault location, accurate, easy maintenance, can significantly improve production efficiency and reduce maintenance costs. Because of the specific test items, is one of the modern mass production quality assurance testing means.
Isolation (Guarding): the actual circuit on the device connected to each other, influence each other, so that Ix Min the ref, the test must be isolation (Guarding). Isolation is the basic technology of the online test.
 On the circuit, R1, R2 connected shunt Ix Min the ref, Rx = Vs / V0 * Rref are equation does not hold. Test, as long as the G and F of the same potential, no current flows through R2, and still have Ix = Iref is the Rx of the equation unchanged. G-point grounding, because of the point F virtual ground potential equal to two o'clock, you can achieve isolation. Practical utility, so that the potential of the G and F by an isolated op amp. ICT tester provides a number of isolated points, to eliminate the influence of the peripheral circuit test.
 IC testing: digital IC, Vector (vector) test. Vector test is similar to the truth table measurements, motivating the input vector, the measurement output vector, the actual logic function test to determine the device is good or bad. Such as: non-door testing of analog IC test, in accordance with the actual functionality of the IC excitation voltage, current, and measuring the corresponding output as a function block test.