Max power draw on voltage rails of mini PCIe Card
The document your looking for is called PCI EXPRESS MINI CARD ELECTROMECHANICAL SPECIFICATION. You can find the PDF on the homepage of the PCI-SIG if you are a member or on your favorite search engine. The most recent revision seems to be 2.1.

In the older version 1.2 I have on hand, it says in 3.4.3 Power:


1100 mA (2750 mA) normal (peak) current on 3.3V
375 mA (500mA) normal (peak) current on 1.5V