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FEATURES *3.6V to 15V Input Voltage Range *3A Output Current per Channel *Up to 95% Efficiency *Low Duty Cycle Operation: 5% at 2.25MHz *Selectable 0°/180°Phase Shift Between Channels *Adjustable Switching Frequency: 500kHz to 4MHz *External Frequency Synchronization *Current Mode Operation for Excellent Line and Load Transient Response * 0.6V Reference Allows Low Output Voltages *User Selectable Burst Mode Operation or Forced Continuous Operation *Output Voltage Tracking and Soft-Start Capability *Short-Circuit Protected *Overvoltage Input and Overtemperature Protection *Low Power 2.5V Linear Regulator Output *Power Good Status 0utputs *Available in(4mmX5mm) QFN-28 and 28-Lead TSS OP Packages DESCRIPTION TheZCC3633 is ahighefficiency, dual-channel monolithic synchronous buck regulator using a controlled on-time, current mode architecture, with phase lockable switching frequency. The two channels can run 180° out of phase, which relaxes the requirementsfor input and output ca-pacitance.The operating supply voltagerange isfrom3.6V to 15V making it suitable for dual cell lithium-ion batteries as well as point of load power supply applications froma 12V or 5V supply. The operatingfrequencyis programmable and synchroniz-able from 500kHz to 4MHz with an external resistor The high frequencycapability allows the use of small surface mount inductors andcapacitors. The unique constant frequency/controlled on-time architecture is idealfor high step-down ratio applications thatoperate athighfrequency while demanding fasttransientresponse.An internal phase lock loop servos the on-time oftheinternal one-shottimer to match the frequency of the internal clock or an applied external clock. The ZCC3633 can select between forced continuous mode andhigh efficiency Burst Mode operation APPLICATIONSD istributed Power Systems Battery Powered Instruments Point of Load Power Supplies |
