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!
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.
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?