AD834 quadrant multiplier

I am trying to build mean square circuit using multiplier AD834. I am using circuit diagram provided in Analog devices application note AN-212. In fig.3 on page 6-41 of this application note there is simple DC to 500MHz Mean Square circuit. When I input 500mvp-p 300KHz I get -210mV across pin 5 and pin 4. When I input 0 volts I get -230mV across pin 5 and pin 4 of AD834. I was expecting 0 volts at these pins. Can anybody help me to find out the reason why the out put is not zero for 0 V input. Also herewith I have attached the table which shows input sine wave value and output DC measured across pin 5 and 4 of AD834. The table shows that the results are not correct. Request you to help me to find out the reason why the circuit is not working as per expectations.

ADC834 INPUT  300KHz sine wave
DC Voltage measured across pin 5 and 4 of AD834
935 mV 211mV
800mV 39.8mV
700mV -64mV
600mV -144mV
500mV -210mV
400mV -257mV
0mV -230mV


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  • The removed resistor was 75 Ohms. Calculated the output values by using your formulas, the results are near to expected values. The inaccuracy may be due to my function generator's internal resistance (50 Ohms). Now I will try with opamp between function generator and Ad834 input.

    I thank you very much for your prompt help. Your answers gave me new vision to see in to the AD834. Thank you once more.

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  • The removed resistor was 75 Ohms. Calculated the output values by using your formulas, the results are near to expected values. The inaccuracy may be due to my function generator's internal resistance (50 Ohms). Now I will try with opamp between function generator and Ad834 input.

    I thank you very much for your prompt help. Your answers gave me new vision to see in to the AD834. Thank you once more.

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