• ADA4940-1 common mode offset V output voltage

    The ADA4940 is being used to buffer the output of an AD9707 TxDAC. This is a circuit we've successfully used before with the ADA4932 differential amplifier. The wider output swing of the 4940 is very helpful in this application.

    I have six prototypes…

  • ADA4940-1作为前放时输出噪声较大

    大家好,我这边正在设计一个210kHz信号调理电路,设计电路如下图所示,增益约为20dB,信号发生器产生210kHz,2mVpp正弦信号接入ADA4940-1输入,发现输出信号噪声较大,之后修改电路,采用交流耦合输入,在输入端串联一个100nF电容后,噪声变好一些,但是还是较差,查看数据手册,发现ADA4940-1的小信号增益曲线在过渡带处存在吉布斯现象(上翘的峰值),不知道是不是这个原因引起的,还有一般ADA4940-1作为ADC驱动,是不是不太合适做前放输入?

  • 关于运算放大器ADA4940-1的一些使用问题

    打算采用ADA4940-1作为精密ADC:AD4001/4003的驱动器,待采集的信号是单端信号,经运放AD8228和AD8250放大之后,采用ADA4940-1转成差分信号。信号采集流程图如下图所示。

    问题1:

    我在ADA4940-1的datasheet中看到需要计算单端输入阻抗,如图66,67所示。由于我在ADA4940-1同相输入端接了可编程增益仪表放大器AD8250的输出端,请问我还需要考虑在AD8250输出端和ADA4940-1的同相端之间增加端接电阻Rt吗?

    问题2:由于AD8250是一个程控增益放大器…

  • RE: ADA4940

    If you do not add an operational amplifier in front of the ADA4940-1, the circuit will still behave normally, but the ADA4940-1 circuit will present a lower impedance to whatever is driving it, compared to an opamp buffer which could generally be configured…

  • 0.1Hz to 10Hz voltage noise of ADA4940-x

    Are there any information available for ADA4940-1/ADA4940-2 about the voltage
    noise density vs. frequency in the range 0.1 to 10Hz? If not, are there
    informations available about the 0.1Hz to 10Hz voltage noise (peak-peak)?

     

    Unfortunately…
  • Here is what I am looking for: I need a low frequency (less than 10kHz) driver, which can drive the 50Ohms DC couple resistor in the testing instruments (like spectrum analyzer, oscilloscope). I found some parts, like ADA4940-1. When I checked its da...

    Here is what I am looking for: I need a low frequency (less than 10kHz) driver, which can drive the 50Ohms DC couple resistor in the testing instruments (like spectrum analyzer, oscilloscope). I found some parts, like ADA4940-1. When I checked its datasheet…

  • RE: ADA4940 Spice Model

    Hi Garth,

    I'm not familiar wit hthe ADA4691 but does it actually simulate any non indeal behavior that the actual amp go through while turning on?

    The only think I can think of is that the model might lower the power but I can not think it would…

  • ADA4940-2

    Hi

    I have a question about the ADA4940.

    When the power supply is not turned on
    How is the absolute maximum rating of VIN?

     

     

    Best Regards

    HOd

  • Driving AD9629 from ADA4940 for programmable input

    Hi,

    I am using ADA4940-1 as differential ended unity gain amplifier for driving AD9629

     Now, as AD9629's Input differential voltage is 2Vp-p, I need to give programmable I/p (negative Sine wave) to the ADA4940's Inverting terminal.

    For Ex:  If…

  • ADA4940 thermal resistance

    I would like to know thermal resistance(j-b), thermal resistance(j-c) and maximum junction temperature for

    ADA4940-2ACPZ-R2