Tool/software:
The DC-IRIS aperture drive circuit on IPC uses LM358. Currently, the test department has found that the output deviation of some LM358 machines is much larger than that of normal machines. The phenomenon is described as follows, please send it to the technical support of suppliers for analysis and processing: The drive circuit and test points of the LM358 are shown below. A to O are voltage test points at different positions
The point between C70 and R55 is used as the signal input point A, input different voltages between 0 and 3.3V, and the point between FB5 and R30 is the output measurement point O, which is used to measure the corresponding output voltages when different inputs are used. It is found that the normal chip and the deviated chip are placed on the same board (all other devices on the board are not moved, and all other devices on the board are not moved. Only replace different LM358). When the input voltage at point A is the same, the voltage deviation at output point O is very large, with a deviation of more than 1V. After many measurements, the deviation is basically stable. Take the voltage at input point A as 1.78V for example, the voltage at different points A to O of the normal chip and the chip with a large deviation is shown in the table:
In view of the above test situation, could you please help analyze the possible reasons and solutions for such a big difference between the input and output of U7A part?
