He worked during the time of Rāmapāla, which ought to be, according to this author, around 1129-1165 (others date his reign to circa 1087-1141, which seems to suit Pa tshab's fuzzy time frame better). Dungkar Rinpoche's dictionary, p. 1256.
More may be learned from the lengthy colophon of the Saddharmasmṛtyupasthāna. And there is mention of him in a mchan-note in Mkhas pa Lde'u's history, p. 304, although I believe the note is in large part mistaken since it equates this Pa tshab with an 8th century translator of the same clan name.
