BUY SA28A https://www.utsource.net/itm/p/760974.html
Transient Suppressor,
SA28A is a NPN silicon epitaxial transistor manufactured by Galaxy Semi-Conductor Co Ltd. It is a general purpose amplifier and switch. The features of SA28A include: High current (max. 800 mA) Low collector-emitter saturation voltage (VCE(sat) = 0.3 V (Max.) @ IC = 500 mA) Low noise figure (NF = 0.5 dB (Typ.) @ f = 1.0 GHz) High gain bandwidth product (fT = 5.0 GHz (Typ.)) The applications of SA28A include: Audio frequency amplifier Low noise amplifier High frequency switch Relay driver High speed switching (For reference only)