NPN silicon transistor encapsulated in a 3-lead plastic SOT54 package. PINNING PIN 1 2 3 base collector emitter DESCRIPTION 1 2 3 BFQ221 MSB033 Fig.1 Simplified outline SOT54. QUICK REFERENCE DATA SYMBOL VCBO IC Ptot fT Cre Tj PARAMETER collector-base voltage collector current (DC) total power d.