SC2643

The SC2643 provides microprocessor core voltage regulation solution up to 4 paralleled PWM channels. The solution can also be configured as 2, 3, or 4-phase form. Multiphase buck regulator utilizes the phase-shift timing control to allow interleaved switching of the power switches.

This architecture minimizes the core voltage ripple and the input current ripple, which leads to optimized voltage regulator design for power density, transient responses, and the thermal performances. To satisfy the highly dynamic nature of the modern microprocessors, the SC2643 adopts peak current mode control topology which ensures wide control loop bandwidth and fast transient responses. The current mode control provides intrinsic phase current matching. The maximum ripple frequency is greater than 4MHz.

One of the outstanding features of the SC2643 is its voltage regulation accuracy. Not only it provides better than 0.5% set point accuracy, but also the accuracy to fully complaint with the stringent load line specifications mandated by the modern microprocessors. Lossless output current sensing ensures that the regulator output voltage is accurately positioned according to the load current condition, and an internal temperature compensation technology further enhances the performance of voltage accuracy.

The patented Combi-SenseTM topology is employed by SC2643. The MOSFET Rds(on) and the output inductor winding
resistance are used to generate the phase current information. SEMTECH Combi-SenseTM MOSFET driver plus the SC2643 enables the complete solution.

The cycle-by-cycle current limit plus the intelligent over current shut down provide the maximum versatility of the system without false tripping under all possible changes of VID and load conditions. The differential voltage feedback sense eliminates the error caused by high load current on the ground plane. The enable function is also provided to interface with the corresponding system signal for correct start up timing and shut down timing.