LSF0102: What happens if VCCA is open?

Hi Zach,

Zach Kimble said:

If I have VCCB = 3.3V and VCCA is open, what voltage should be expected at VCCA? Is it left floating if its voltage is greater than VCCB - Vth?

Note that we will not be able to guarantee its' operation as this is not a recommended condition. However, Vref_B is connected internally to the gate and drain of internal MOSFET. Hence, yes; when the transistor is turned on, the vref_A is pulled to Vref_B - Vt.

Zach Kimble said:

Also, if VCCA is shorted to ground, how much current flows into VCCA? Is it approximately VCCB/200kOhm (ignoring the relatively small ON resistance of the FET)?

Also yes, as with Vth accounted for it's typically (Vref_B-Vref_A-Vth) /200K. 

Best Regards,

Michael.