Hi there,
My customer is designing ADA4937-1 to drive AD9284 for his project. He follow AD9284-250EBZ schematic design, however there are some questions.
1) In EVB circuit, ADA4937-1 IN+ & IN- are swapped compared to Fig19 in AD9284 DS. Is there any…
我的电路图如上图所示，其中ADA4937-1输出端的电阻应该是0欧姆。
两个运放电路一模一样。
我现在的问题是，不供任何信号，就这样的电路，加上电后，频谱仪设置为0-100MHz，幅度为-120~-20dB。
这个时候就可以看到，70MHz附近会有个一些信号抬起来。大概比噪底-70dB提高5dB左右。
实在找不到原因。
另外还有一个问题。调制器IQ数据的滤波电容改成560pF对100MHz带宽数据有没有影响？
Hi,
My customer wnats to get your advice about their schematic with AD9251-80 and ADA4937-1.
They used AD9251-65 and ADA4937-1 in their system, but now they will change the sampling frequency of their system.
So they need your help.
The sampling frequency…
I'm simulating the ADA4937 Differential Ampliifier that I will use as ADC driver for the AD9255, with and without output filter.
It seems that adding the output filter at tha ADA4937 leads to a huge distortion of the output signal.
Dear Flaviano,
Thank you for using the ADA4937 and AD9253.
I believe that the output common mode range of the ADA4937 is not quite matched to the AD9253. As you have stated, the VCM output of the AD9253 is at 0.9V. This is outside the range of the ADA4937…
Hi Tarzan,
A gain of 0.5 V/V might work with AD8138 but not with ADA4937. It is advised that the gain of the ADA4937 would be 0.8 V/V or higher to ensure stability.
Regards.
How to drive AD9637 use 3 pcs ADA4937-2? What's the connnection about the 6 Vocm pins of 3 pcs ADA4937-2 to the Vcm pin of AD9637? Thanks!
Hello,
The typical offset drift for the AD9265 is +/-2 ppm/C which corresponds to +/-4 uV/C with a full-scale span of 2 Vp.p.
The ADA4937-1 is specified at 1 uV/C typ but this applies to its input only and its output offset drift would be dependent…
Apologies for late response.
#1 & #2. Input Common Mode Voltage Range of ADA4937 is specified at Min = 0.3 V to Max= 3.0 V. Within these specified values the part is expected to have an optimum operation. You go beyond this limits, the outputs…
My customer request your confirmation about their schematic.
They used AD9251-65 and ADA4937-1 to LTE ICS Repeater.
But now they want to change ADC from AD9251-65 to AD9258-125.
As you know, these two devices are pin compatible, so they want…