Other Parts Discussed in Thread: DAC8568,
Using the iinternal reference of DAC, Vref=2.5025V when all channels don't output. If one channel output 2.4V, Vref will transfer to 2.5033V. When more channels output, Vref will be more and more high. If all channels output 5V, Vref is changed to 2.510V.Because Vref is changed, the output voltage of channel is changed,affecting the accuracy of production.
The ref pin of chip has 100nf(0603) and 1uf(0603) capacitors.
Tested DAC8568, no the problem.
DAC80508使用内部参考,通道不输出的时候内部参考Vref=2.5025V,通道1输出2.4V,Vref变为2.5033V,随着通道输出的增到,Vref持续增大,当8通道都输出5V的时候,Vref变大到2.510V,由于Vref变化,输出的电压值也发生变化,影响产品精度了。
DAC80508 REF脚上有100nf(0603)、1uF(0603)的电容.
测试DAC8568,没发现这个问题。