AD633: input coupling

Q

I have connected AD9850 and AD633 like in the attached diagram. AD9850 outputs
0-1000mV sine wave, and a 0.1uF capacitor is placed between AD9850 and AD633.
The AD633 is powered by +-5V, and the 2nd pin is connected to GND. I found:
1. If cutting off the wire between the 0.1uF capacitor and AD633, then the
voltage after the capacitor is +/-500mV;
2. If connecting the capacitor and the AD633, then the voltage at the 1st pin
of AD633 will be 0 -1000mV.

A

The AD633 inputs require a voltage source drive, so you need a buffer between
the 9850 and pin 1. The circuit needs a dc source and won’t operate with
capacitive coupling.

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