My design: Two cascade connected inverting amplifiers.
My problem: The output of second amplifier is saturated from -0.6 to -0.7V. The supply of OPAMPs is dual (+5-5V).
What is the problem? How can I fix it?
Note 1: Input is a 2V sinusoidal wave.
Note 2: Output of second OPAMP is connected Analog Multiplexer (ADG708).
Best Answer
The ADG708 can only handle negative inputs if it's in the -2.5 to 2.5V dual supply configuration. If you've got it hooked up to 0 and 5V, then that makes complete sense. There will be protection diodes in the ADG708 that will clamp to -0.7 or so below it's lower rail (VSS).