My design drives this device with -16V for an intended regulated output of -15

Problem: no output (-0.3v or so).

The EN pin is tied to the -16V input.

Then, I read the data sheet:

Absolute Maximum Ratings

EN to GND 5 V to VIN

EN to VIN +30 V to −0.3 V

Pin Configurations and Function Descriptions

EN     Drive EN 2 V above or below ground to enable the regulator, or drive EN to ground to turn off the regulator. For           automatic startup, connect EN to VIN.

These seem ambiguous.  VIN is -16V, well below the -0.3V absolute maximum for the EN pin.  The data sheet can't be right.

I hesitate to tie EN to +5V until I hear from the experts.