The TC105 is a step-down (Buck) switching controller that furnishes output currents of up to 1A (max) while delivering a typical ... The TC105 is a step-down (Buck) switching controller that furnishes output currents of up to 1A (max) whiledelivering a typical efficiency of 92%. The TC105 normally operates in pulse width modulation mode (PWM), but automatically switches PFM/PWM Step-Down DC/DC Controller