The 2N5551 and SOC5551 are bipolar transistors able to operate under severe environment conditions and radiation exposure providing high immunity to total ionizing dose (TID). Qualified as per ESCC 5202/019 specification and available in LCC-3 and UB hermetic packages, they are specifically recommended for space and harsh environment applications and suitable for low current and high precision circuits such preamplifiers, oscillators, current mirror configuration. In case of discrepancies between this datasheet and the relevant agency specification, the latter takes precedence.