SMP402

SMP402 1-Watt Buck Regulator IC 20-72 VDC Input Non-isolated DC Output Product Highlights Integrated Power Switch and CMOS Controller Output power > 1 W from 48 VDC input Adjustable output voltage Integrated solution minimizes overall size High-voltage, Low-capacitance MOSFET Output Designed for ISDN T1 telecommunications applications Low capacitance allows for high frequency operation High-voltage Buck Regulator Internal pre-regulator self-powers the IC on start-up Designed for low power consumption Minimum external parts required Built-In Self-protection Circuits Undervoltage lockout Thermal shutdown Input polarity/level sense SMP402 + 48 VDC - ® + 5 VDC - PI-555A-123091 Figure 1. Typical Application. Description The SMP402, intended for non-isolated ISDN telecommunications power supply applications, combines a high voltage power MOSFET switch with a switchmode power system controller in a monolithic integrated circuit. Few external components are required to implement a low cost power supply which meets stringent ISDN specifications. High frequency operation reduces total power supply size. The P-channel power MOSFET switch features include high voltage, low RDS(ON), and low capacitance. Lower capacitance results in a reduction in gate drive power, and also facilitates higher frequency operation. The controller section of the SMP402 contains all the blocks required to drive and control the power stage: start-up preregulator circuit, oscillator, b...