col_implant
New Member
I wanted to shift and gain 1Khz signal generated with a Vp-p of 625mV and a Voffset of 625mV to an AC coupled 1.6Vp-p signal. To do this i have used a simple active high pass filter shown in the figure...i use the TSH80 amplifier from ST.My gain is 2.5 and the cuttoff frequency is about 200Hz. Pretty simple.. right?
For some reason the output signal is giving an offset of about -160mV. The offset appears to decrease slightly as i increase the cuttoff frequency (by decreasing capacitance). Even when I set the input signal to DC i still get an offset of about -100mV even though i do not measure any offset at the amplifiers input terminal. Apart from this output offset the amplifier appears to be working perfectly. There is no mention of an output offset voltage in the amplifier datasheet
Is there some silly error i am making? Is my amplifier broken? Is there a better circuit or a simple inprovement i can make to the existing circuit?
Thanks
For some reason the output signal is giving an offset of about -160mV. The offset appears to decrease slightly as i increase the cuttoff frequency (by decreasing capacitance). Even when I set the input signal to DC i still get an offset of about -100mV even though i do not measure any offset at the amplifiers input terminal. Apart from this output offset the amplifier appears to be working perfectly. There is no mention of an output offset voltage in the amplifier datasheet
Is there some silly error i am making? Is my amplifier broken? Is there a better circuit or a simple inprovement i can make to the existing circuit?
Thanks