The SP3485E chip can be judged by the following methods:
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Appearance check: Check whether the surface of the chip is damaged, deformed, discolored and other abnormal conditions.
Pin measurement: Use a multimeter to measure that the pin of the chip is in good contact and the pin resistance value is within the normal range.
Functional test: Through the circuit board test chip input, output, control signal, etc., is normal.
Reliability test: carry out high temperature, low temperature, humidity and other tests to check the reliability and stability of the chip.
If the above methods meet the requirements, you can judge that the chip is good. However, it should be noted that safety needs to be paid attention to when testing the chip to avoid electric shocks or damage to the device.
Mainly to see what type of chip, some chips can be judged good or bad by measuring DC resistance, but some models can not be judged by this method, you need to check the details of the chip refer to the function and parameters of the pin to judge, there is a special chip tester can judge the quality of the chip