3. Tracopower 2A Step-Down Switching Regulator, TSR 2 Series. New and advanced ultra-compact range of SIP packaged step down regulators from Tracopower. The TSR 2 series offers a direct drop-in upgrade to the antiquated LMxx series. Boasting up to 96% efficiency without the need for extra heat dissipation such as a heat sink. Another main benefit of the TSR 2 series is the significant advantage of using switching regulators over linear variants. Benefits for making the transition include better output accuracy and a lower standby current. Features and Benefits. Compatible with the LMxx series linear regulators. Integral short circuit protection.