For the 350 ohm bridge sensor circuit, in the aduc7061 without the use of internal PGA, how to select an external amplifying circuit 300 times?

  • Why do you want to use a external amplifier, because the internal already provides gain up to 512?

    What other requirements are critical for your design - BW, slewrate, offeset voltage, bias current ... ?

    This questions may be better answered on the amplifier community!



    Analog Microcontroller

    Community Manager



    ADUC7060 for 4-20mA loop processing, taking into account the internal PGA power is too large, and the maximum PGA gain is 64, the rest is a digital gain. Can you provide the ADC low power mode PGA consumption power? Modeled on the CN0216_00_1024.gif, can change ADA4528 to ADA4051-2? ( Amplify 301 times.jpg ). In ADA4051-2 data manual input resistance is written with 8M, Amplify 301 times.jpg operational amplifier input resistance calculated how? My English level is limited, please forgive.

  • Hi abcdoaabc,

    The ADA4051-2 does have low Vos, Vos drift and lower power consumption of 20uA. But, note that the voltage noise density of the part is about 16x higher than the ADA4528-1. This trade-off is expected for a low power amplifier.

    The higher Vn increases total noise, reduces the number of noise-free counts and reduces the noise-free resolution of the system. A word of caution, you won’t be able to achieve the same performance that you could with the ADA4528-1.

    If you would like to maintain an equivalent resolution as shown in CN0216, use the ADA4528-1. For better performance, you might be better off using the PGA in AduC7061.



  • Thank you for your reply, I have now from your company purchased 1000 piece of ada4051-2, which makes me very headache.

  • MSP430 ADUC7061 power did not do well, the kernel frequency 320K ( 1.5mA ), ADC > = 128 ( 630uA ), for the 4-20mA circuit occupies a relatively large power consumption. If in front of the ADC added instrumentation amplifier, how?