AT1792

AT1792 Preliminary Product Information 2A/18V/300KHz Step-Down Voltage Regulator Feature ‧ 4.75V to 18V Supply Voltage Operating ‧ ‧ ‧ ‧ ‧ ‧ ‧ ‧ ‧ ‧ ‧ ‧ Range. 300KHz Fixed Switching Frequency. Voltage-Mode PWM Step-Down Regulator. Built-in Power MOSFET, Rds(on)≒100mΩ. 2A Output Current, Up to 91.9% Efficiency 1.225V±1.5% Internal Reference Shutdown Current less than 25uA. Built-in Soft-Start. Cycle-by-Cycle Current-Limit Protection. Short Circuitry Protection. Under-Voltage Lockout Protection. Output Voltage Adjustable up to 16V. SOP-8 Package. Description AT1792 is a voltage-mode PWM step-down DC-DC converter capable of driving up to 2A loads over a wide input supply range with excellent line and load regulation characteristics. High efficiency is obtained through the use of a low Rds(on) P-channel power switch. It uses a fixed switching frequency up to 300KHz thus allowing smaller sized components. The output voltage level is user-programmable via an external resistive voltage divider. The built-in soft-start can reduce inrush current on the input source at turn on. The device also has built-in cycle-by-cycle current-limit, under-voltage lockout and an ON/OFF logic-control that can power down the regulator to a shutdown mode. In shutdown mode the regulator draws less than 20uA of supply current. When a short circuit is detected on the output , the device immediately change switching frequency to 32 KHz and duty cycle is limited to 5% to protect IC from damage. AT1792 is available in SOP-8 package. Application ‧ Distributed Power Systems ‧ Battery Charger. ‧ Palmtop Computers, PDAs. ‧ DSL Modems Block Diagram EN Regulator Under-voltage lockout Current Sense Amplifier Current Sense + Contol Logic P-MOS VIN SCP OSC 32/600KHz PWM Comparator Error Amplifier + 1.225V FB SoftStart SW Aimtron reserves the right without notice to change this circuitry and specifications. 7F, No.9, PARK AVENUE II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C. Tel: 886-3-563-0878 Fax: 886-3-563-0879 WWW: http://www.aimtron.com.tw 11/21/2007 REV:0.5 Email: service@aimtron.com.tw 1 + GND COMP AT1792 Preliminary Product Information 2A/18V/300KHz Step-Down Voltage Regulator Pin Configuration SOP-8 TOP- VIEW 1 2 3 4 NC IN SW GND NC EN 8 7 COMP 6 FB 5 Ordering Information Part number AT1792X_GRE ▲▲▲▲▲ Package SOP-8, Green Marking 792, Date Code with one bottom line : Date Code *For more marking information, contact out sales representative directly Pin Descriptions Pin No. Symbol I/O Description 1 2 3 4 5 6 7 8 N/C IN SW GND FB COMP EN N/C P O P I O I No Connect Power Input. IN supplies power to the IC and Step-down converter switch. IN must be bypassed with a ceramic 0.1uF capacitor. Power Switching Output. Ground. Feedback Input. Connect a resistive divider from switching output to FB to ground. Error Amplifier Output. A series RC network connected to this pin compensates AT1792. Enable input. EN is a digital input that turns the regulator on/off. Drive EN high to turn on the regulator, drive it low to turn it off. No Connect 7F, No.9, PARK AVENUE II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C. Tel: 886-3-563-0878 Fax: 886-3-563-0879 WWW: http://www.aimtron.com.tw 11/21/2007 REV:0.5 Email: service@aimtron.com.tw 2 AT1792 Preliminary Product Information 2A/18V/300KHz Step-Down Voltage Regulator Absolute Maximum Ratings *1 Parameter IN voltage EN voltage SW voltage FB, COMP voltage Quiescent current HBM ESD Susceptibility*3 MM Rated Value -0.3 to 20 -0.3 to 5 -1 to IN+1 -0.3 to 6 5 2 200 unit V V V V mA KV V 1. Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. 2. Measured on approximately 1” square of 1 oz. copper FR4 board. 3. Device are ESD sensitive. Handling precaution recommended. The Human Body model is a 100pF capacitor discharged through a 1.5KΩ resistor into each pin. Recommended Operation Conditions Parameter Power supply voltage Operating temperature Symbol Min. IN Top 4.75 -20 Values Typ. 12 +25 Max. 18 +85 Unit V ℃ 7F, No.9, PARK AVENUE II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C. Tel: 886-3-563-0878 Fax: 886-3-563-0879 WWW: http://www.aimtron.com.tw 11/21/2007 REV:0.5 Email: service@aimtron.com.tw 3 AT1792 Preliminary Product Information 2A/18V/300KHz Step-Down Voltage Regulator Electrical Characteristics (IN=12V, EN=5V, Ta=+25℃, unless otherwise noted) Parameter Input operating voltage Input under-voltage lockout threshold UVLO hysteresis Quiescent Current Shutdown Current Oscillator Frequency Short-Circuit Frequency Feedback Regulation voltage FB Input Bias Current Current limit Maximum Duty Cycle Minimum Duty Cycle SW Switch On-Resistance SW Leakage Current Load Regulation Line Regulation Error Amplifier Trans-conductance Soft-Start Time EN Threshold Voltage EN Pull Up Current Symbol IN VUVLO Test Condition IN Rising Min. 4.75 3.8 - Typ. 12 4.2 700 3.5 25 300 32 Max. Units 18 4.6 50 330 V V mV mA uA KHz KHz V nA A % % mΩ µA % 400 %/V µA/V ms V µA Iin ISHDN fSW VFB IFB DMAIN DMIIN RSW-DS(ON) ISW VFB=1.5V EN =GND Ta=+25℃ FB=0V Ta=+25℃ VFB=1.225V Min. On-time>0.5µs FB=1.0V FB=1.5V ISW=2A IN=13.5V,VSW=GND , EN=0V 0 A