SSTA28 / MMSTA28 is a 1/2 NPN general purpose transistor produced by ROHM Semiconductor. Its features are BVCES < 80V (Ic=100µA).
The document details the SSTA28 and MMSTA28 NPN general-purpose transistors, available in SOT-23 (SST3) and SC-59 (SMT3) packages. It lists absolute maximum ratings such as a collector-base voltage of 80V and a collector power dissipation of 0.3W.