Important notice Dear Customer, On 7 February 2017 the former NXP Standard Product business became a new company with the tradename Nexperia. Nexperia is an industry leading supplier of Discrete, Logic and PowerMOS semiconductors with its focus on the automotive, industrial, computing, consumer and wearable application markets In data sheets and application notes which still contain NXP or Philips Semiconductors references, use the references to Nexperia, as shown below. Instead of PSSI2021SAY Constant current source in SOT353 package Rev. 03 27 August 2009 Product data sheet 1. Product prole 1.1 General description Resistor-equipped PNP transistor with two diodes on one chip in a SOT353 (SC-88A) plastic package. Stabilized output current of between 15 A and 50 mA by connection of an external resistor between pins 4 and 5. 1.2 Features n One chip integrated constant current source n Output current setting by use of an external resistor n Very small package n Reduces component count and board space 1.3 Applications n Automotive applications n Generic constant current source n Constant current LED driver n Active bias control for audio ampliers 1.4 Quick reference data Table 1. Quick reference data Symbol Parameter Conditions Min Typ Max Unit I output current 0.015 - 50 mA out V supply voltage - - 75 V S