Found a bag of N-CH MOSFET MARKED TN5CO

About 13 in there strip holder. Transisitor checker states "N-E-MOS" C=188, Vt=1.4v"
Any idear what transistor this might be before I toss them (or keep them)? They are tiny SMA parts, but the middle lead and back does seem to be a heat-sink for the part.
Is there a chart anywhere that can translate SMT markings to a real part number?