IC is good or bad how to check the [components procurement]
Update date：2012-8-7
Do electronic procurement people know that we will encounter in the procurement process renovation of IC, the original IC, domestic IC, sometimes there are bad IC, how do we detect it? Also in the actual electronic process, how to detect the the PCBA above IC if bad, how rapid detection of these techniques a lot of people may not know that East guide science and technology today to sum up.
(A) The commonly used detection methods most commonly used detection method in IC testing online measurement, non-line measurement method and substitution method. A. Line measurement on-line measurement method is the use of the voltage measurement, resistance measurement and current measurement, the pin voltage value by the measurement of integrated circuits on the circuit, the resistance values and current values are normal, to determine the damage of the IC .
Two. Off-line measurements, off-line measurement tide when the IC is not welded into the circuit by measuring the DC resistance between its pins with the known normal model IC DC resistance between each pin compared to determine whether normal.
3. Substitution method, this is the most direct detection methods, and buy a new IC, replace what you can not confirm, so can most directly determine whether the IC is damaged. (B) commonly used in integrated circuit testing. Microprocessor microprocessor integrated circuits integrated circuit testing pin is a VDD power supply terminal RESET reset port, XIN crystal oscillator signal input XOUT becomes to the crystal oscillator signal output and the other line input and output. Different types of microprocessor RESET reset voltage is not the same, some low reset, that is low in the instant boot, reset to maintain high; some high reset switching transients for high maintain low after reset. Two. The detection of the switching power supply IC switching power supply IC pin voltage power supply terminal (VCC), the output end of the excitation pulse, the voltage detection input current detection input. Measuring voltage and resistance value of each pin to ground, and the normal large difference in the normal circumstances of their external components can be determined that the IC is damaged.
3. Detection and inspection of the audio amplifier integrated circuit audio amplifier IC to detect the power supply terminal (positive power supply terminal and a negative power supply terminal), audio input, audio output and feedback side-to-ground voltage and resistance values. If the pin measured data value and normal value of its peripheral components and normal, it is the IC internal damage. Cause silent failure of the audio amplifier IC to measure the normal supply voltage, signal interference method available to check. Measurements, the multimeter should be placed in the R × 1 files, red table pen ground, with the black pen touch audio input, the normal speaker should be a strong "Titicaca" sound.
4. The op amp IC testing with a multimeter DC voltage profile, measuring the voltage between the op amp output and the negative supply-side (in a static high voltage). Two handheld metal tweezers in turn touch the op amp input (by adding the interfering signals), the multimeter hands more substantial swing, then the op amp is in good condition;. Multimeter hands does not move, then the op amp has been damaged.
5 Time base IC testing integrated circuits containing digital and analog circuits with a multimeter is difficult to directly measure its quality.
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