I wonder what communication method (i2c, UART, SPI) does AD9235 use and which pin is for communication. And if I want to achieve full 20MSPS, what is the minimum frequency of CLK source. Is Arduino Uno R3 powerful/fast enough to communicate with AD9235…

Hello,

Could you please advise me the minimum input frequency of AD9235 without an influence of external capacitor? I would like to use AD9235 by wide frequency range.

And how about the AD9649 and AD9266? Is it same as AD9235?

Best regards,

Akira

AD9235的单端输入中的0.33uF电容可否改为电阻，

请教ADI工程师，我想用AD9235-65芯片，我的输入信号频率50K左右，输入信号经过滤波后，离AD9235的距离很近，是不是就不需要单端转差分输入了？我的信号本来是单端的。或者更进一步，在什么情况下才需要单端转差分信号？谢谢！

在AD9235的数据手册中，对单端输入有这样一个图：

这个图的2Vp-p是指的0~2V的信号吗？在数据手册第17页左侧中部，对于0~2V单端输入电路，又有这样的说明：

这句话的意思不是说当单端输入0~2V时，VIN-接1V，VIN+接信号输入就行吗？为什么还要像上图一样那么接呢？

还有。当VIN-接1V，VIN+接0~2V时，输出的数字信号是怎么样的呢？在数据手册中并没有找到明确的关于数字输出的说明

Hi,

I have a question inner circuit for AD9235 .

I woukld like to know inner sample hold time for AD9235-20,-40,-65.

My customer wants to know it,

So if you like , Please tell me sample hold time..

Best regards

honkawad

向各位大师请教几个问题，我使用ad9235与fpga电路进行一个简单的最大值判断电路。一个类似正玄信号（周期性的）模拟输入，通过ad9235之后利用fpga在其最大值处进行一些操作。同时我通过在fpga中编程设一个阈值，滤除低于阈值的信号，程序不对这些值进行操作。

1）发现刚上电时，信号一直有，但是电路并未作出找到最大值得操作，而是工作大概10S后才能找到最大值稳定的工作。不知这是由于什么问题引起的？

2）我发现把阈值放低了的话，fpga会找不到最大值，而把阈值提高，最后又能找到阈值了，这是的确不合逻辑…

Hello,

According to AD9235 datasheet. There are 2 type of input circuit.

On page 16, Figure 35, AD8138 Positive output go to AD9235 VIN+, negative one go to VIN-.

On the other hand, page 23, Figure 46 shows analog input circuit on AD9235 EVM that…

Hello,

In the datasheet of the AD9235 there is a specification for gain drift when using an external reference. 

is there any data available regarding typical gain drift when using the internal reference?

Best Regards

Norman Werner