The peak forward voltage is 1.2@1A according to the datasheets.This device consumes about 2@Ta=55C continuous forward current at any given time.To operate, a DC reverse voltage less than 800 must be used.
JAN1N4947 Features
the forward peak voltage is 1.2@1A
JAN1N4947 Applications
There are a lot of Semtech JAN1N4947 applications of RF diodes.