The MAX14591 datasheet is confusing with regards to VL voltage.
In the Electrical Characteristics (EC) table, under "Power Supply Range" VL is listed as min 0.9V and max is 5.5V. So this says VL can operate from 0.9V to 5.5V. However, the conditions in which the EC table was created lists VL = +0.9V to min(VCC + 0.3V, +3.6V). In addition, note 3 on page 4 lists: "Note 3: VL must be less than or equal to VCC during normal operation. However, VL can be greater than VCC during startup and shutdown conditions.", and on page 10 under "Level Translation", it says "For proper operation, ensure that +1.65V < VCC < +5.5V, and +0.9V < VL < VCC."
So what does all this mean? What are the limits of VL?
- VL is not limited to 3.6V. As long as VL < Vcc, the part will operate fine. If VL is above 3.6V, your specs may vary from those in the Electrical Characteristics table, but operation will be unaffected.
- VL has an absolute maximum voltage of 6V. For this to operate, Vcc would also have to be 6V.
- VL can be higfher than Vcc at startup, but not during normal operation
- VL can be as low as 0.9V