FAQ
Hi,
While I am using PulSAR ADC PMODs and picked AD7690. I have the findings and questions listed below.
我在计算过采样对AD7690 SNR的改善。
公式如下。在我的应用中,带宽为150Hz。但我不确定N的值。对于AD7690,N应当是18位还是16.6位?
Hello,
Hopefully someone may be able to help me out...
I am testing out an AD7690 18-bit ADC for an application. Currently I can get a reading from the ADC, though it is not what I expect.
Vref is set to 2.048 V and there is 1.45 V onto IN+, IN- is…
现在有个项目,传感器信号输入为-5~+5v, 经过AD8475进行0.4倍衰减并移位到2.5伏后,再差分进入AD7690进行数据采集。当该传感器输入电压很小时,AD7690差分数据采集偏差很大;但如果传感器输入电压较大时,AD7690差分数据采集很准。
具体如下表:
AD7690输入差分电压 AD7690输出结果
0.4mv 2mv附近跳动,最大到5mv
1mv 4mv附近跳动,最大到8mv
2mv 比较准确
3mv 很准
。。。 很准
电路连接是参考AD8475与AD7690的数据手册中的推荐电路的…
Hi Vijay,
Sorry for the late reply. The AD7690 is a fully differential input. This means the positive and negative inputs must be antiphase around the common mode voltage Vref/2, the IN- pin cannot be tied to ground for proper operation. Is 18 bit performance…
I recently built the reference design included with the AD8295 datasheet, which uses the AD8295 to differentially drive an AD7690 ADC chip. This is a very compact implementation but I can't seem to get it to work correctly.
That said, I notice that…
1.数模转换
传感器出来的数据一般都是模拟量,也就是我们通常所说的电压值(当然也有电流值的,这时我们可以通过一个精密电阻把其转换为电压值)。如果把这些模拟量变成计算机能够处理的数字量呢?这时就要使用我们的数模转换器,俗称AD。
在我的这个项目中,模拟量的提供者是一个非常灵敏并且线性度很好的水平传感器,该传感器的满量程输出为5V/14.5°,按次推算如果采用3.3v基准的16位AD则其分辨率为0.00014°,采用3.3v基准的18位AD则其分辨率为0.000036°。(不考虑各种误差)
…