rackland@csis.dit.csiro.au (Ross Ackland) (04/09/91)
I am in the process of designing an A/D circuit to interface to a PC/AT bus. I will use two Analog Devices AD7820's (1uSec conversion time) and have finished the digital side of the design (address decoding etc) but I am now struggling with the analogue side. The signals I am trying to digitise swing between +/- 2.5 volts and they are sampled at random intervals as close as 5 uSec apart (with the mean sampling interval about 50mSec). The input to the A/D's requires non bipolar input (0 - Vref) and so if I select a Vref of 2.5 volts I need to scale the input and add a bit of DC offset (preferably derived from the voltage reference). Can anyone help me with this? Perhaps reccomend an Op-Amp with adequate bandwidth, slew rate etc.. that would be suitable, or even some good references or text books on Op Amp design, maybe even a circuit suggestion. Thanks in advance Ross Ackland ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Internet : rackland@csis.dit.csiro.au Voice : +61-6-2750911 Fax : +61-6-2571052 Physical : CSIRO Division of Information Technology, GPO Box 664, Canberra ACT 2601 AUSTRALIA ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~