The datasheets state that the peak forward voltage is 0.39.A continuous forward current of about 1 can be consumed by this device at any given time.In order to operate, you will need a DC reverse voltage less than 40.
SSL14 R2 Features
the forward peak voltage is 0.39
SSL14 R2 Applications
There are a lot of Taiwan Semiconductor SSL14 R2 applications of RF diodes.