Currently am using AD8352 AC coupled differential amplifier to drive ADC AD9445, It is working fine for sine wave input with any frequency... The problem is whenever we try to apply a pulse input with varied duty cycle to differential amplifier it introduces an undesired DC OFFSET at the output....... what modification shall i make to work amplifier properly ( provides the clean output except DC OFFSET) with an varied duty cycle.... Am attaching the schematic....any help would be appreciated.....
The input to the amplifier has a high pass arrangement (R337+C930; R430 +C932). This might be the reason the pulse isnt going through. Oscilloscope plots at the input and output nodes will tell us more.
Based on the high pass filter arrangement, the theoretical -3 dB cutoff frequency of that network is 31.8 KHz. At what frequency are you applying the pulsed input signal?
Thank you for ur valuable information....... Am applying the input clock with upto 50MHz, What would i do to make this circuit working for my input requirement.....
thank u umesh....... what would i do to make this circuit working for clock input with upto 50MHz, without introducing DC offset at the o/p.........
I know you mentioned on your earlier post that you were applying a pulsed input with a varied duty cycle. Other than a sine or pulsed input, have you tried applying a square, triangle, or saw-tooth wave input with variable frequency and duty cycle? Also, make sure that the DC offset of the generator you are using is not introducing any DC offset to your generated signal. Some oscilloscope output plots would be really helpful in allowing us to see what exactly is going on with the circuitry.