Right here, Zman :-)
The reason the input impedance is not evident from the datasheet is that it depends on the configuration of the surrounding circuit. Assuming that the input stage is used in the inverting configuration shown in the figures on pages 7 and 16, the input impedance is equal to the value of resistor Ri, the resistor that is in series with the input signal. As you can see, that is shown as 20K for the application depicted on page 7, but it may be significantly different than that for other applications.
Regards,
-- Al
The reason the input impedance is not evident from the datasheet is that it depends on the configuration of the surrounding circuit. Assuming that the input stage is used in the inverting configuration shown in the figures on pages 7 and 16, the input impedance is equal to the value of resistor Ri, the resistor that is in series with the input signal. As you can see, that is shown as 20K for the application depicted on page 7, but it may be significantly different than that for other applications.
Regards,
-- Al