Other Parts Discussed in Thread: DAC7811
I need a some assistance selecting a topology to achieve a variable gain amplifier with gain range of 0 to +200, for a VREF input of varying positive voltage (0 to +5V). Figure 21 in the datasheet for the DAC8811, shows a positive output configuration for a static VREF input.
The datasheet suggests that the circuit in this figure should be used rather than following the I/V converter with an additional inverting stage due to resistor tolerance errors. For a variable positive input, would I alter the setup in figure 21 by adding a summing amplifier between the shown input amplifier and the VREF input to sum the negative reference and the input signal? This would still need to be followed by a gain stage of +200, so resistor tolerances would come into play anyway. I'm inclined to simply follow the output amplifier with an inverting stage with a gain of -200. Could the DAC8811 be configured in "reverse" as shown in the reference design notes for the DAC7811 (tiduaf0.pdf)? Is there a better way to achieve my goal?
