I use LMH6521 for the small siganl.
the input signal is 300mV ( differantial ), and it's common mode voltage is 2.5V
and LMH6521 output common mode voltage is 4.4V . is that correct ?
the gain register is 0x80 , it means the gain is 26dB.
1.
when i add a 0.1uH inductance to the output between the out + and the GND , the out- and the GND.
the output res is 50Ω, and with a 0.1uF cap series connection .
the output siganl become very small . it seems less than 100mV.
2.
without the inductance , res and cap . i can get 1.2V signal output .
Question :
does the output signal common mode voltage correct ?
why i just get 12dB gain when i use nothing on the output ?
why the signal is become very small when i use the recommend circuit ?
how can i get the 26dB gain ?