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I am designing a system that incorporates the ADC12DL040 ADC. Page 27 of the datasheet gives the following example schematic for converting a single-ended signal into a 1V +/- 0.5V differential signal as required by the inputs to the ADC:
With the following table for the values of the unspecified resistors:
My signal input ranges from 0-0.5V, so I used the resistor values in the second row. I am trying to simulate the amp in LTspice with the following schematic:
However, simulating a 0-0.5V linear DC sweep produces the following output, rather than two 1V +/- 0.5V signals:
Any idea where the circuit is going wrong? Thanks!
Hi William,
I used Tina () to simulate the circuit. Here is the file I used AnalogInput_0to0.5V.TSC.
Looking at the circuit, you can see that I tied the DC voltage that is feeding into the non-inverting input of OP4 into the non-inverting input of OP3. This way, both inputs will share the DC offset (common-mode) of 1V and are 180 degrees out of phase (90 and -90). Also, you will notice that the amplitude of the output at both VIN+ and VIN- is 1V. This meets the requirements in the data sheet (Seen below) of 1V +/-0.5V.
Is this what you were looking for?
Regards,
Dan
