BUY BZA820A https://www.utsource.net/itm/p/11286427.html
BZA820A TVS/ESD 20V SOT-353/SC-88A marking Z4
The BZA820A is a NPN Bipolar Transistor manufactured by NXP/Philips. It is housed in a SOT-353/SC-88A package. Description: The BZA820A is a low-noise, high-gain NPN transistor designed for use in a wide range of audio and general purpose applications. Features: Low noise High gain Low saturation voltage Low collector-emitter saturation voltage High current gain High switching speed Applications: Audio amplifiers High-frequency switching High-frequency amplifiers Voltage regulators Motor control circuits Low-noise amplifiers (For reference only)