The LM397 device is a single voltage comparator with an input common mode that includes ground. The LM397 is designed to operate from a single 5-V to 30-V power supply or a split power supply. Its low supply current is virtually independent of the magnitude of the supply voltage.
The LM397 features an open-collector output stage. This allows the connection of an external resistor at the output. The output can directly interface with TTL, CMOS and other logic levels, by tying the resistor to different voltage levels (level translator).
The LM397 is available in the space-saving 5-Pin SOT-23 package and is pin-compatible to TI’s TL331, a single differential comparator.