Other Parts Discussed in Thread: ADS8904B
Hi,
I have a couple of questions pertaining to the usage of the THS4551 as the single-ended to differential driver of the ADS8904B. This use case is depicted in Figure 111 of the ADS8904B datasheet (see below).
1. Could you please explain the function of the 10 ohm resistors that are circled in red in the figure below? I gather from the documentation that the 2.2 ohm resistor and 10 nF are for filtering, but I’m not clear as to the role of the 10 ohm resistors. Are these for filtering as well or do they serve some other function?
EDIT: Please ignore the question below about the "+" or "-" input. I just realized it's already addressed in another post.
2. Is the input indicated by the red arrow the “+” or “-“ input or does it depend on my application? In other words, if I want the THS4551 to be inverting, I would use the “+” input; for non-inverting, I’d use the “-“ input. Is there any advantage to configuring the THS4551 as inverting instead of non-inverting or vice-versa? The reason I ask is that the datasheets and app notes typically show an FDA configured as inverting (i.e. “+” input connected to GND either directly or through a resistor), which makes me wonder if the inverting configuration is somehow advantageous. I suspect it’s not and that the inverting configuration is simply more popular for whatever reason, but thought I would ask the question just to confirm.
Regards,
James
