• RE: AD7658-1 tconv > 3.1us

    Hi AllisonM,

       The maximum conversion time of the AD7658-1 is 3.1us across the Tmin to Tmax temperature range. The AD7658-1 conversion time was gathered in specific condition mentioned on page 7 (upper portion of the page). I can see that the AD7658-1 is…

  • 急急急:AD7658-1运行一段时间后无响应,busy信号一直为0

    您好,我最近用AD7658-1做采样,芯片配置为硬件模式,16bit并行接口,2*vref模拟输入范围,使用FPGA做驱动接口,电路板上电后,芯片采样正常,过一段时间(大概几个小时不定),AD芯片无响应,busy信号一直是0,无法恢复。重新上电后又恢复正常。可能是哪里的问题呢?

    下面是AD7658-1的硬件原理图

    下面是正常采样的时候FPGA发出的convert和AD芯片返回的busy信号

    下面是正常采样的时候FPGA发出的convert和read信号

    下面是正常采样的时候AD芯片返回的b…

  • RE: AD7658, queries for current consumption

    Hi Karen,

    Thank you very much for your answer.

    In regards to supply current, please let me ask you more.

    About the feature of the analog input, how does it different between AD7658 and AD7658-1 ?

    If it is clear what is different, we may assume why…

  • AD7658 -reading data

    Hello.

    I've got little problem with reading data from AD7658. I am using it in hardware and parallel mode. After power up, sending pulse signal to reset pin (with CONVST X high) and the high-to-low CONVST edge followed by a low-to-high CONVST edge, I…

  • About AD7658 Specifications

    Hi all,

     

    I use the AD7658 in Serial Mode(SER/PAR^/SEL = HIGH).

    There are two questions about characteristics.

     

    ①Timing in Serial Read Operation

     

    According to Figure 32, data is valid after the falling edge of SCLK.

    This is specified as the minimum of…

  • AD7658 output comnparison problem

    Hi all,

    I'm using ad7658 in parallel mode. I have written my own fpga code to read the analog inputs. In simulation it works regularly but i can't see the true results at the outputs when i change it input voltage value.

    In oscilloscope, the…

  • RE: 请教ADI工程师AD7658设计问题

    建议你使用AD7658-1,对去耦的要求降低,更方便使用。您的电源方案是可以的,建议用线性稳压器,譬如ADP7102。关于驱动输入芯片,选取手册上推荐的元件即可。如果想详细了解驱动放大器参数和ADC的关系,请参考此文章:

    http://www.analog.com/library/analogDialogue/archives/46-12/sar_front_end.html

  • AD7658的正负供电电源问题

        最近正想用AD7658采集双极性信号,AD7658要求要用双极性的供电电源,有没有一款电源芯片能够将单极性的正电源输入转换为对称的双极性的电源输出,这样使用双极性的AD芯片就方便多了。以前用7812跟7912搭建的正负12V的电源太笨拙了…………

  • AD7658转换正常,但是没有输出

    最近在用FPGA配一块AD7658芯片,   并行输出到FPGA。发现输出不读,然后我就用chipscope抓了下信号线,如下:

    可是,无论我输入是多少,抓出来的数据都是 0111 1111 1111(第一路数据,也就是ad_rd的第一个低电平对应的数据,这个芯片支持六路)。

    现在是我把ad_convsta拉高以后,ad_busy跟着拉高,按手册上的说法应该是ad已经进入了转换模式了,ad_busy也正常拉低,可是读出来就是不对,时钟是500KHz。困扰我两天了。

    这是手册上的时序图:

  • AD7656/AD7657/AD7658: What order is channel data presented in serial mode, single DOUT line

    In the serial data mode for a single data line configuration can you tell me in
    which order channel data is presented on the DOUT line. This information is
    provided in the datasheet only for the parallel interface.

     

    In the case of using…