I have designed a 1Mohm, 0Hz-100MHz fixed attenuator circuit (15pf/300pf). I am using 1%, C0G capacitors. There is also a TS5A2053 analog switch connected to the output of the attenuator. The switch will add 18.5pf of capacitance to ground (typical). I will layout the PCB to minimize stray capacitance and I will tune the values to that layout.
My question is, when this ckt is produced in volume how much variation in the capacitance ratio should I expect to see from unit to unit? And what are the causes of this variation?
Obviously the capacitors (+/-1%) themselves will yield +/-2%. The resistors are negligible. C0G should not change much with age? Would soldering change the value? How much variation should I expect from the analog switch (only "typical" is specified)?
Edit: Sorry, I was vague about the schematic; but to be specific, it is a simple voltage divider - two resistors and two capacitors.
Edit: I have found several sources which say that the capacitance of a mosfet does NOT vary with temperature. So, the capacitance of my analog switch will not likely vary with temp - I think only the switch's initial capacitance will vary due to process differences (thickness of the diffusion channel?).