Dear Pro，
The output voltage of some chips is inaccurate.See the figure below for the outsourcing circuit of the voltage reference chip: 3.3VDC input, and the voltage of 3.0VDC is generated as the reference voltage of the single-chip ADC.
The input voltage of 3.3v is also stable and there is no problem in the power supply voltage for chips such as SCM /SDRAM.But the output reference of some chip is not accurate.(at present, 40 boards have been tested, and 3 output benchmarks are inaccurate)
I conducted a separate electrification test on the abnormal REF3130AIDBZR chip and found that its output voltage changed with the input voltage.
When the power supply is 3.3v, the no-load output voltage is about 1.9v.If connected to the MCU, the output voltage becomes about 1.5v;
As the supply voltage increases, so does the output.
Please help me analyze what causes this kind of problem.I checked the screen printing of the device, and the specification is correct.
