AIC1401 Step-Down DC/DC Controller with Shutdown n FEATURES l l l l l l l l n DESCRIPTION Operation Voltage up to 15V Voltage-Mode Operation The AIC1401 is a high efficiency, PWM step- Fast Transient Response Built In Accurate 1.3V Voltage Reference Adjustable Over Current Protection using RDS(ON) No External Current Sense Resistor Required Low Shutdown Current suitable for IA, Notebook, LCD PC and LCD 200KHz Free-Running Oscillator Built in Soft Start. higher cost P-channel MOSFET in a standard down, voltage-mode, switching controller. It is monitor main power applications. The built-in high voltage CMOS driver drives an external N-channel MOSFET for replacing the buck topology. n APPLICATIONS l l l l l Notebook PC Advanced PC Mboards Information PCs The 200KHz switching frequency allows using Servers and Workstations PC Add-On Cards bandwidth and 6V/us slew rate of the error smaller external components while maintaining high conversion amplifier efficiency. ensures the The higher 11MHz converter bandwidth and the fast transient response. The AIC1401 also features over current protection. It provides adjustable over current trigger point and short-circuit protections by sensing the output current across the on resistance of the external N-channel MOSFET rather then an expensive external low value sense resistor. n ORDERING INFORMATION AIC1401CXXX PIN CONFIGURATION PACKING TYPE TR: TAPE & REEL TB: TUBE PACKAGE TYPE S: SMALL OUTLINE SO8 TOP VIEW OCSET 1 8 VCC S HDN 2 7 UG COMP 3 6 LX FB 4 5 GND Example: AIC1401CSTR a in SO-8 Package & Taping & Reel Packing Type Analog Integrations Corporation 4F, 9 Industry E. 9th Rd, Science-Based Industrial Park, Hsinchu, Taiwan TEL: 886-3-5772500 FAX: 886-3-5772510 www.analog.com.tw DS-1401-00 012102 1 AIC1401 n TYPICAL APPLICATION CIRCUIT C2 1000P R1 R5 10 *C1 2.2K 12V 1F *C1 must be very close L1 to VCC PIN OCSET C5 R2 33P FB C6 + VCC SHDN COMP M1 UG C3 470F IR3303 LX GND R6 L2 5K 7H AIC1401 D1 90.9K 5V 1.5H 1000P SRA1620 R4 R3 13K 2K VOUT 1.5V/5A + C4 330FX3 DC/DC Converter n ABSOLUTE MAXIMUM RATINGS Supply Voltage, VCC ....... ...... ... ... ............................... ... ... ... ......................................... 15V Input, Output, or I/O Voltage .................. ... ... ... ... ... ....... ... ......... GND - 0.3V to VCC+0.3V ESD Classification ................................ ... ... ... ........ ... ................. ... ......................... Class 2 Recommended Operating Conditions Supply Voltage, VCC....... ......................... ... ... ... .......... ... ... .................................. 12V 10% Ambient Temperature Range .... ................................... ... ... ... .... ... ... .................. 0C~70C Junction Temperature Range ....... ............... ... ... ............ ..... ... ......................... 0C~ 100C Thermal Information Thermal Resistance, JA (Typical, Note 1) SOIC Package .................................. ... ... ... ... ... ... ... ... ..... ... ... ... ... ........... . 100C/W SOIC Package (with 3 in 2 of Copper) ... ... ... ... ... ... ... ... ... ... ... ... ... ... ......... .. 90C/W Maximum Junction Temperature (Plastic Package) ... ... ... .... ... ..... ... ... ................... 150C Maximum Storage Temperature Range ... ... ... ... ..... ... ... ... ......... ... .... ......... -65C~150C Maximum Lead Temperature (Soldering 10 Sec) ... ... ... ... ... ... ... ...... ... ......... ......... 300C Note 1: JA is measured with the component mounted on an evaluation PC board in free air. n TEST CIRCUIT Refer to TYPICAL APPLICATION CIRCUIT. 2 AIC1401 n ELECTRICAL CHARACTERISTICS (VCC= 12V, T A=25C, unless otherwise specified.) PARAMETER TEST CONDITIONS SYMBOL MIN. TYP. MAX. UNIT VCC Supply Current Nominal Supply UGATE Open IVCC 2 mA 9.5 V Frequency 200 KHz Duty Cycle 88 % Power-On Reset VCC Threshold VOCSET=4.5V Oscillator Internal Reference Voltage 1.27 Reference Voltage 1.30 1.33 V Error Amplifier DC Gain 76 dB GBW 11 MHz SR 6 V/S Upper Gate Source RUGATE 7 Upper Gate Sink RUGATE 5 IOCSET 200 A ISS 10 A Gain-Bandwidth Product Slew Rate Gate Driver Protection OCSET Current Source SS Current VOCSET =4.5VDC Shutdown Shutdown Low Input VIN L Shutdown High Input VIN H Shutdown Mode Current 0.35 2 V V 1 A 3 AIC1401 n TYPICAL PERFORMANCE CHARACTERISTICS Efficiency vs. Load Current OCSET Current vs. Temperature 100 Vo=1.3V 80 200 Vo=2.0V Clset (A) Efficiency (%) 90 70 Vo=3.5V 60 50 198 Tc=134ppm/ C@ 0~100C 196 194 40 192 30 1 2 3 4 5 6 IOUT (A) 7 8 Over-Current Operation 9 10 11 -40 -20 0 20 40 60 80 100 Temperature ( C) 120 140 160 Output Clamped by Built-In Soft Start Transient Response 4 AIC1401 n BLOCK DIAGRAM Over Current - LX + OCSET SHDN 200A Power-On Reset Built-In Soft Start + - VCC PWM Comparator REF Error AMP + Gate Control UGATE - FB GND COMP Oscilator n PIN DESCRIPTIONS PIN 1: OCSET- Current limit sense pin. Connect a resistor ROCSET from this pin to the drain of the external MOSFET. ROCSET, an internal 200A current source (IOCSET), and the external MOSFET onresistance (RDS(ON)) jointly set the overcurrent trip point according to the following equation: IPEAK = PIN 2: PIN 4: FB - The error amplifier inverting input pin. The FB pin and COMP pin are used to compensate the voltage-control feedback loop. PIN 5: GND - Ground pin. PIN 6: LX - Overcurrent detection pin. Connect the LX pin to source of the external N-MOSFET. This pin detects the voltage drop across the MOSFET RDS(ON) for overcurrent protection. PIN 7: UG - External MOSFET gate drive pin. Connect this pin to gate of the external MOSFET. PIN 8: VCC - The chip power supply pin. Recommended supply voltage is 12V. IOCSET R DS(ON) SHDN - Shutdown pin. Connect this pin to ground for shutdown. PIN 3: COMP - External compensation pin. This pin is connected to error amplifier output and PWM comparator. A RC network is connected to FB pin to compensate the voltage-control n feedback loop of the converter. APPLICATION CIRCUIT Refer to TYPICAL APPLICATION CIRCUIT 5 AIC1401 PHYSICAL DIMENSIONS l 8 LEAD PLASTIC SO (unit: mm) D H E e SYMBOL MIN MAX A 1.35 1.75 A1 0.10 0.25 B 0.33 0.51 C 0.19 0.25 D 4.80 5.00 E 3.80 4.00 e 1.27(TYP) A C A1 n B H 5.80 6.20 L 0.40 1.27 L 6