Re: Driving ADC, please help

Question

Hi Ramon, 
 You could use a basic inverting opamp config with the ADA4841-1 
 http://www.analog.com/static/imported-files/tutorials/MT-213.pdf 
 Rin would be twice Rf. You could use 5V and ground as the supplies. However the limitations are you may lose some range near ground and near 5V (maybe 50-100mV depending on head/footroom spec). Also the input impedance is dictated by Rin, so not a high impedance input. Is the positive supply fixed at 12V? 
 Best Rgds, 
 Alan

ADIApproved · Accepted Answer

Hi Ramon, 
 Please see the following tutorial pages 6,7 and 8 
 http://www.analog.com/static/imported-files/seminars_webcasts/High%20Speed%20System%20Applications%20(PDF)/HS%20Systems%20Part%202%20for%20Print_A.pdf 
 On page 7 you want to use config C as i have described. In this scenario there is no issue haivng 10V inputs with a 5V supply. Both opamp inputs will sit at 3.33V. This config has been used in this circuit note 
 http://www.analog.com/static/imported-files/circuit_notes/CN0254.pdf 
 You could use a resistor divider followed by a buffer stage if you wish. Make sure the buffer supply has enough headroom for the signal range you require. 
 Best Rgds, 
 Alan)

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Re: Driving ADC, please help

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