Greetings to All,
Unexpectedly I've faced a problem with Analog Devices IC. I'm hoping for your help.
To test the circuit I use two signals: 40 MHz at X1 input, 1kHz at Y1 input. Both signals are single ended and fed through a series capacitors, X2 and Y2 are grounded. Although frequencies are relatively low, I used proper supply decoupling capacitors as it is advised in the datasheet.
1) What I see at W output does look like a sum of the signals at X1 and Y1 inputs. I see no multiplication.
2) The other thing that confuses me is that I see -1.68V DC at X1 and Y1 inputs. Is that correct and AD835 should have these DC voltages at inputs? Is it correct to feed AD835 with AC coupled signals?