Data document for the 2sb1590k, a 34.8 KB PDF listed under schematics. The 2SB part follows JIS numbering for PNP low-frequency bipolar transistors; the trailing K is a variant suffix whose exact meaning, often a package or grade, should be confirmed inside the sheet rather than assumed. Use the document for pinout, maximum ratings, hFE classes and the surface marking code. Make sure the suffix variant matches the part fitted on the board, since different versions can use different packages or lead arrangements.
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