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AD8015 Common Mode Voltage

Question asked by mathison on Jun 15, 2017
Latest reply on Jun 19, 2017 by Dongfeng



I will use the AD8015 for my design, there is a datasheet detail that I don't quiet understand and I don't have a SPICE model neither the real part to check right now.


My questions are about the AD8015's differential output (cf. AD8015 datasheet, REV. A, page -2-) :


1)    I can see that the Output Voltage Swing is almost divided by 2 when it's 50 Ohm loaded/adapted, why it is equal to 600mVpp and not 1Vpp/2 = 500mV refer to the High Impedance (Rl = infinite) measurement ?


2)    I power the cheap up by applying +5V on +Vs (pin 8) and 0V on -Vs (pin 5), so the Output Common Mode Voltage is supposed to be 5 - 1,3 = +3,7V ? for High Impedance Load or 50 Ohm Load ? Is - it auto adjustable and always equal 3,6V no matter the load, or is it divided by two when adapted, or divided by two plus something unknown in the document (like the voltage swing case) ?


Thank you for your answer !