This part is a kind of semiconductor called L4950.

Function of this product has (L4945 - L4951) 5V/8.5V/10V VERY LOW DROP VOLTAGE REGULATORS.

Manufacturers : SGS-THOMSON

Image and pinout :

Some of the text within the PDF file :

L4945/L4950 L4951 5V/8.5V/10V VERY LOW DROP VOLTAGE REGULATORS PRECISE OUTPUT VOLTAGE: 5V ± 4% (L4945) 8.5V ± 4% (L4950) 10V ± 4% (L4951) OVER FULL TEMPERATURE RANGE (– 40 / 125 °C) VERY LOW VOLTAGE DROP (0.75Vmax) OVER FULL TEMPERATURE RANGE OUTPUT CURRENT UP TO 500mA OVERVOLTAGE AND REVERSE VOLTAGE PROTECTIONS REVERSE VOLTAGE PROTECTION SHORT CIRCUIT PROTECTION AND THERMAL SHUT-DOWN (with hysteresis) LOW START UP CURRENT DESCRIPTION The devices are a monolithic integrated circuit in Versawatt package specially designed to provide a stabilized supply voltage for automotive and industrial electronic systems. Thanks to their very BLOCK DIAGRAM TO220 ORDERING NUMBER: L4945 L4950 L4951 low voltage drop, in automotive applications the devices can work correctly even during the cranking [ ... ]

L4950 PDF Datasheet Download