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AMC1100 / detail of block diagram and resolution

Ryuji
Guru 20090 points
Other Parts Discussed in Thread: AMC1100, AMC1204

Hello,

Could I have the detail of AMC1100 block diagram ?
Can I use block diagram in the following URL one ?
http://e2e.ti.com/support/amplifiers/precision_amplifiers/f/14/t/330584.aspx

Also, I think that AMC1100 transmit the data by digital.
That means AMC1100 have ADC.  
Could you please let me know the resolution of that ADC ( same specification of AMC1204) ?

Best Regards,
Ryuji Asaka

  • 0
    TI__Genius 9975 points

    Hello Ryuji Asaka,

    As you indicated in your forum post, the block diagram in the forum post below corresponds to the AMC1100.

    http://e2e.ti.com/support/amplifiers/precision_amplifiers/f/14/t/330584.aspx

    The AMC1100 has a delta-sigma modulator whose theory of operation is very similar to that of the AMC1204; however, we cannot provide any specific performance metrics other than those described in the AMC1100 (which takes into account the performance of both the delta-sigma modulator and the recovery circuitry).

    Hope this helps.

    Best regards,

    Jose

  • 0 in reply to Jose Duenas
    Guru 20090 points
    Hello Jose san,
     
    Sorry for bothering you.
    I got the questions from our customer again.


    (1) about Resolution
    AMC1100 has delta-siguma modulator(ADC) and  recovery circuitry(DAC).
    So I think that these have the resolution.
    Could you please let me know these resolution ?
    If we can't , could you please let me know the calculation example of output acuracy ?
     
    (2) Gain error total
    Could you please let me know min/max value of Rin?
    There is the calculation of Gain error total in the equation of datasheet p.14.
    In this equation, Gain error total is decided by Gain error and external register and Rin.
    However Rin is specified by typical value only.

    If there are not min/max data , should I calculate the total gain error by typical value of Rin?
     
    Best Regards,
    Ryuji Asaka
     
     
  • 0 in reply to Ryuji
    TI__Genius 9975 points

    Hello Ryuji-san,

    It is impossible to provide performance metrics on the recovery circuitry because its input is not accessible. One can only measure the performance of the entire signal chain from analog input in pins 2 and 3 to analog outputs in pins 6 and 7. The intermediate steps are not accessible outside of the integrated circuit and cannot be measured.

    The output accuracy depends on the following factors: a) offset, b) gain error, c) thermal drift, d) non-linearity, e) common mode of input signal.

    As you point out, the source impedance plays a role in the gain error calculation; however, the value of Rin is calculated as shown in page 10 of the AMC1100 datasheet (see figure 31). With this in mind, there is no sense in specifying a minimum or maximum value for Rin.

    In order to better quantify the error caused by R1 and R2 (as shown in page 14 of the AMC1100 datasheet), could you please send a schematic of the analog input to the AMC1100? What are the values of R1 and R2 in you circuit?

    Also: what is the operating temperature of the circuit and what are the values of the voltages applied to L1 and L2 with respect to pin 4 of the AMC1100? What is the maximum differential voltage applied to  pins 2 and 3 of the AMC1100?

    Best regards,

    Jose

     

  • 0 in reply to Jose Duenas
    Guru 20090 points

    Hello Jose san,

    Thank you very much for your reply and sorry for my late responce.
    I got the reply from our local FAE about calculation of Gain error total.

    Also, our customer use 450kohms of R1 and 470ohms of R2.
    L1 , L2 voltage is 100VAC.

    Best Regards,
    Ryuji Asaka

  • 0 in reply to Ryuji
    TI__Genius 9975 points

    Hello Ryuji-san,

    Based on those values for R1 and R2, I think the equations provided in the AMC1100 datasheet will provide conservative gain error figures that your customer should be able to use for their gain error budget.

    Best regards,

    Jose