R8 is known as the attenuation resistor, and is used to attenuate the output by setting the top half of a voltage divider circuit, with the bottom half supplied by the load, such as an internal termination of the oscilloscope. TI does not recommend to populate with a low value resistor as the output of the comparator is not able to drive such a load as the amount of current sourced is significant. A 1kΩ resistor is recommended for this footprint which, coupled with an internal 50Ω termination of the scope creates an attenuation factor of 1:21 which can be rectified using oscilloscope settings. A high speed probe can be used for measurement of the output, but rise and fall times can be limited.

Two types of output connections are supplied depending on the needed configuration. J5, an SMA connector, can be populated or J10, a two-pin jumper, can be populated if using an active probe. If measuring the output and input (via input sense connections J3 and J4), TI recommends to use length matched cables on the output and sense lines to minimize distortion issues.

Figure 2-3 Output Side Block Diagram