• Driver AD9253 using ADA4937

    Hi,

    I have designed a circuit by using an ADA4937-1. I used it to drive ad AD9253-125.

    As shown in the picture attached, the input is a single ended Vpp = 1,6V.

    The Vcm of the ADC is qual to 0,9V but, using this voltage as Vocm for ADA4937, the signal…

  • ADA4937 Output series Resistor

    I'll drive the 14-bit AD9255 ADC, sampling a 35MHz signal at 88MHz, with a ADA4937.

    I read a couple of application notes, like AN742.

    So, "the key is to make the input look as "real" as possible to achieve a good impedance match".…

  • ADA4937-1的问题

    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?

  • ADA4937 input impedance - 1k or 50R?

    I'm using the ADA4937 as a buffer/driver for the AD9649BCPZ-40 ADC.

    My system is required to have 1k input impedance.  The current line-up is: input -> anti-alias LPF -> ADA4937 -> differential RLC LPF -> AD9649BCPZ-40.

    Would it be better…

  • ADA4937的输出问题

    我在做一个AD采集系统的时候,使用到ADA4937芯片来进行信号的幅度处理,输入信号为正弦波,幅度为+/-3.3V的差分信号,需要处理为幅度为0-2V的差分信号,

    原理图为上图所示,现原理图中的RF和RG的值都修改为200ohm,闭环增益为1,在AD_VIN,2+,AD_VIN2-没有输入的情况下,ADC_INP2输出电压为0.8V,ADC_INN2输出电压为2.4V,通道1同理,不管我怎么调试RF和RG电阻的阻值,和VOCM的电压值,输出始终不变。

    很简单的一个电路,不知道为什么会出现这个问题…

  • Request Schematic Review about AD9258-125 and ADA4937-1

    Hello,

    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…

  • Inquiry about the design of the AD9258 and the ADA4937-1

    Hello,

    My customer will use ADA4937-1 and AD9258 at repeater application.

    1. Input voltage range of the Vocm pin in the ADA4937-1 is min 1.2V to max 3.8V. However, the VCM output of the AD9258 is 0.9V.

        The voltage ranges between the Vocm pin and the…

  • Request the schematic review with AD9251-80 and ADA4937-1

    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…

  • What is the maximum output voltage of the ADA4937 with 3V3 single supply?

    What is the maximum output voltage of the ADA4937 with 3V3 single supply?
    I have ADS42LB49 and its maximum analog input voltage is 3V, is it safe to use
    without protection diodes while the ADC is driven by ADA4937 ?

    Best Regards
    Yavuz

  • JPEG Processing - 4:2:2 v 4:2:0?

    My JPEG saga continue...

    I am using a BF561 single core to compress a 640x480 YUV 4:2:2 image into JPEG format, employing the ADI JPEG Library tools.  I am getting very poor performance compared with the reference results from the Spec Sheet.  The Spec…