Operating Principle

The chip contains a voltage divider with a comparator at each resistor.
The points between the resistors of the voltage divider go to the + side of each comparator
The input signal goes to the - side of each comparator.

Pins

Number	Symbol	Name
4	RLO	Divider (low end)
5	SIG	Signal Input
6	RHI	Divider (high end)
7	REFOUT	Reference Output
8	REFADJ	Reference Adjust
9	MODE	Mode Select

REFADJ and REFOUT

The chip provides a stable voltage of 1.25 Volt between REFADJ and REFOUT.

RLO

The RLO input goes to the low end of the voltage divider.
If we want the lowest measured voltage to be 0V, connect pin 4 to ground.
If we want the lowest measured voltage to be higher than 0V, connect pin 4 to a voltage divider.

RHI

The RHI input goes to the high end of the voltage divider.

SIG

The SIG input signal goes to the - side of each comparator.

In the simplest configuration:

REFADJ is ground and RLO is connected to ground REFOUT is connected to RHI so that the low end of the reference is connected to the low end of the divider the high end of the reference (1.25 V) is connected to the high end of the divider

Thus making the voltage range of the circuit 0 V to 1.25 V.