RT9245B

RT9245B is a multi-phase buck DC/DC controller integrated with all control functions for AMD K8 CPU. The RT9245B could be operated with 2, 3 or 4 buck switching stages operating in interleaved phase set automatically. The multiphase architecture provides high output current while maintaining low power dissipation on power devices and low stress on input and output capacitors. The high equivalent operating frequency also reduces the component dimension and the output voltage ripple in load transient.
RT9245B implements both voltage and current loops to achieve good regulation, response and power stage thermal balance.
RT9245B applies the DCR sensing technology newly. The RT9245B extracts the ESR of output inductor as sense component to deliver a precise load line regulation and good thermal balance for next generation processor application.
Current sense setting, droop tuning, V_CORE initial offset and over current protection are independent on compensation circuit of voltage loop. The feature greatly facilitates the flexibility of CPU power supply design and tuning. The DAC output of RT9245B supports AMD K8 6-bit VID, precise offset value & smooth V_CORE transient at V_ID jump. The IC monitors the V_CORE voltage for PGOOD and over-voltage protection. Soft-start, over-current protection and programmable under-voltage lockout are also provided to assure the safety of microprocessor and power system. The RT9245B comes to a small footprint package TSSOP-28.