Description:
Yes, the POWR1220AT8 device can be used to monitor negative voltage with the addition of some simple external circuitry.
The inputs of the POWR1220AT8 device may accept signals from 0 to 6 V without the addition of external circuitry.
For monitoring negative voltages I recommend that you review AN6051 which describes several techniques to interface a negative voltage to the VMON inputs using external components. AN6051, Monitoring and Controlling Negative Power Supplies with Power Manager Devices is available from the Lattice website at the following link:
AN6051, Monitoring and Controlling Negative Power Supplies with Power Manager Devices