About the ADCMP572's circuit of comparator with ±1 V input range and 3.3 V CML outputs (Figure3 of ADCMP572's Datasheet).

Hi, Guys.

I have a question about figure23 of ADCMP572's datasheet.

There is a discripsion "GND = -1V" in the figure.

Could you please advise me the  "GND = -1V" mean?  (If that means is that GND pin (#13and#15) connects -1V, ADCMP572's output Level of  "Low" is also -1V.)

Best regards,

Yuki.