XXRRPP77665577 22AA,, 2255VV NNoonn SSyynncchhrroonnoouuss PPWWMM SStteepp DDoowwnn RReegguullaattoorr February 2011 Rev. 2.0.0 GENERAL DESCRIPTION APPLICATIONS The XRP7657 is a non synchronous voltage Distributed Power Architectures mode PWM step down (buck) regulator Point of Load Converters capable of a constant output current up to 2Amps. A wide 4.75V to 25V input voltage Audio-Video Equipments range allows for single supply operations from Medical & Industrial Equipments industry standard 5V, 12V and 24V power rails. FEATURES With a 420kHz constant operating frequency and integrated high side switch, the XRP7657 2A Constant Output Current reduces the overall component count and 4.75V to 25V Wide Input Voltage solution footprint. In addition to a 2% output setpoint accuracy, this device provides high PWM Voltage Mode Control efficiency, low ripple and excellent line and 420kHz Constant Operations load regulation. An enable function and soft Up to 94% Efficiency start feature allow for controlled power up sequencing implementation. Adjustable Output Voltage 0.8V to 21V Range Built-in over current, output short-circuit and over temperature protection insure safe 2% Accuracy operations under abnormal operating Soft-Start and Enable Function conditions. Built-in Thermal, Over Current and The XRP7657 is offered in a RoHS compliant, Output Short Circuit Protection green/halogen free 8-pin SOIC package. RoHS Compliant, Green/Halogen Free 8-Pin SOIC Package TYPICAL APPLICATION DIAGRAM Fig. 1: XRP7657 Application Diagram Exar Corporation www.exar.com 48720 Kato Road, Fremont CA 94538, USA Tel. +1 510 668-7000 Fax. +1 510 668-7001 XXRRPP77665577 22AA,, 2255VV NNoonn SSyynncchhrroonnoouuss PPWWMM SStteepp DDoowwnn RReegguullaattoorr ABSOLUTE MAXIMUM RATINGS OPERATING RATINGS These are stress ratings only and functional operation of Input Voltage Range V .............................. 4.75V to 25V IN the device at these ratings or any other above those Output Voltage Range V ............................ 0.8V to 21V OUT indicated in the operation sections of the specifications Junction Temperature T Range ................. -40C to 125C J below is not implied. Exposure to absolute maximum Thermal Resistance JA rating conditions for extended periods of time may affect (junction to ambient, no heat sink, free air) ........100C/W reliability. V ............................................................ -0.3V to 30V IN COMP, FB pin voltage .................................... -0.3V to 6V SW, EN pin voltage ...................................... -0.3V to V IN Storage Temperature .............................. -65C to 150C Power Dissipation ................................ Internally Limited Junction Temperature T ....................................... 150C J Lead Temperature (Soldering, 10 sec) ................... 260C ESD Rating (HBM - Human Body Model) .................... 2kV ELECTRICAL SPECIFICATIONS Specifications with standard type are for an Ambient Temperature of T = 25C only limits applying over the full Operating A Junction Temperature range are denoted by a . Minimum and Maximum limits are guaranteed through test, design, or statistical correlation. Typical values represent the most likely parametric norm at T = 25C, and are provided for reference A purposes only. Unless otherwise indicated, V = 12V, V = 5V, T = 25C. IN OUT A Parameter Min. Typ. Max. Units Conditions Input Voltage V 4.75 25 IN Shutdown Quiescent Current 44 60 A V =0.4V EN I SHDN Quiescent Current I 1.3 2.5 mA V =2.0V, V =1.3V Q EN FB Feedback Voltage V 0.784 0.800 0.816 V V =5V to 25V FB IN Feedback Bias Current I -0.1 -0.5 A V =1.3V FB FB Switch Current Limit I 3.4 A LIM 2.5 Oscillator Frequency f 336 420 504 kHz OSC V =0.52V, Current limit activated or FB Oscillator Frequency f 40 kHz OSC1 short circuit protection mode Error Amplifier Voltage Gain G 1000 V/V V Error Amplifier 700 A/V Transconductance G S EN Pin Threshold High V 1.5 V H EN Pin Threshold Low V 0.7 V L EN Pin Input Leakage Current I -5 -10 A V =2.5V EN EN Internal PMOS ON Resistance V = V =12V, V =0.65V, I =12A 130 150 m IN EN FB OUT R DS(ON) Maximum Duty Cycle D 100 % V =0.65V, I =0.1A MAX FB SW Thermal Shutdown T 155 C OTSD Thermal Shutdown Hysteresis 20 C T HYS 2011 Exar Corporation 2/11 Rev. 2.0.0