SC2446 Datasheet | SEMTECH

Description The SC2446 is a high-frequency dual synchronous stepdown switching power supply controller. It provides outof-phase high-current output gate drives to all N-channel MOSFET power stages. The SC2446 operates in synchronous continuous-conduction mode. Both phases are capable of maintaining regulation with sourcing or sinking load currents, making the SC2446 suitable for generating both VDDQ and the tracking VTT for DDR applications. The SC2446 employs fixed frequency peak current-mode control for the ease of frequency pensation and fast transient response. The dual-phase step-down controllers of the SC2446 can be configured to provide two individually controlled and regulated outputs or a single output with shared current in each phase. The Step-down controllers operate from an input of at least 4.7V and are capable of regulating outputs as low as 0.5V The step-down controllers in the SC2446 have the provision to sense a synthesized MOSFET RDS(ON) for current-mode control. This sensing scheme (U.S. patent 6,441,597) eliminates the need of the current-sense resistor and is more noise-immune than direct sensing of the high-side or the low-side MOSFET voltage. Precise current-sensing with sense resistor is optional. Individual soft-start and overload shutdown timer is included in each step-down controller. The SC2446 implements hiccup overload protection. In two-phase singleoutput configuration, the master timer controls the softstart and overload shutdown functions of both controllers. Features ‹ 2-Phase synchronous continuous conduction mode ‹ ‹ ‹ ‹ ‹ ‹ ‹ ‹ ‹ ‹ ‹ ‹ ‹ ‹ ‹ ‹ ‹ ‹ for high efficiency step-down converters Out of phase operation for low input current ripples Output source and sink currents Fixed frequency peak current-mode control 75m V/-110m V maximum current sense voltage Synthesized MOSFET RDS(ON) current-sensing for low-cost applications Optional resistor current-sensing for precise currentlimit Dual outputs or 2-phase single output...