13 Replies Latest reply on Nov 28, 2012 5:09 AM by rajivv_36

    some problems about INSAMP

      hello everyone!


      I have some problems when I try to implement a project with amplifiers. the PSoC is CY8C29466, the input is a dc voltage from 0 to 15mv from a sensor, I want to achieve an output in the range 0 to 5V. 


       I selected a 3 op-amps and set the gain. however when I want to add a PGA after the INSAMP I find it seems impossible, can anybody tell me how to do that? btw, if i use a 2 op-amps it's possible...


      the second problem is about the AGND, as is showed in the data sheet, the AGND is Vdd/2, and also can be set by the parameter ref mux in the global resource. since my interest signal is alwasy positive, so I tried to set Vss as  reference voltage for 2 op-amp INSAMP and PGA, but the noise is quite big and  I even can't observe the output signal...what's more, this method is impossible for 3 op-amp INSAMP. so I want to know may I set the "ref mux" p2[4]+/-p2[6] then connect p24 to GND and p26 to VSS?
      thank you for your help!