GENERAL DESCRIPTION
Current mode operation provides fast transient response and eases loop stabilization. Fault condition protection includes cycle-by-cycle current limiting and thermal shutdown. In shutdown mode the regulator draws 23μA of supply current. APPLICATION z PC Monitors z Distributed Power Systems FEATURES
z 1.5A Output Current z 0.5Ω Internal Power MOSFET Switch z Stable with Low ESR Output Ceramic Capacitors z Up to 95% Efficiency z 23µA Shutdown Mode z Fixed 380KHz Frequency z Thermal Shutdown z Cycle-by-Cycle Over Current Protection z Wide 4.75V to 24V Operating Input Range z Output Adjustable from 1.13V to 18V z Programmable Under Voltage Lockout z Available in 8-Pin SOP8 Packages z Battery Charger z Pre-Regulator for Linear Regulators TYPICAL APPLICATION CIRCUIT PIN ASSIGNMENT Figure 1 PT1109_DSB Rev EN_0.3 SOP8 Page1 PT1109 1.5A,24V,380KHz Step-Down Converter PIN DESCRIPTIONS SOP8 PIN No. 1 2 3 4 5 6 7 8 PIN NAMES BS IN SW GND FB COMP EN NC DESCRIPTION
Bootstrap (C5) - This capacitor is needed to drive the power switch’s gate above the supply voltage.
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