Arduino Analog Read Current Draw

I read some articles and realized that the Arduino uses a Voltage Comparator for the Analog read, correct?

The issue is that I want to have the arduino hooked up in series with this and other circuitry, but I am concerned about degradation of the signal strength.

How much current does the Arduino draw for the analog in?

As far as voltage coming off this line the range should be between 0-3.7V, and around 2.5V on average.

From:
http://www.atmel.com/dyn/resources/prod_documents/doc2545.pdf
p 310.
Analog input resistance (RAIN) 100Mohm.

More here: http://www.atmel.com/dyn/resources/prod_documents/doc2559.pdf

the Arduino uses a Voltage Comparator for the Analog read,

The vast majority of Analogue to digital converters feed the input into a comparator, arduino or not. As pointed out these have a high input impedance.

Thank you, I figured so, due to the idea that voltmeters ideally have infinite resistance, however I wasn't sure about comparator circuits.

I appreciate the posts.