AIC1574

AIC1574 5-bit DAC, Synchronous PWM Power Regulator with Triple Linear Controllers n FEATURES l l n DESCRIPTION The AIC1574 combines a synchronous voltage mode controller with three linear controller as well as the monitoring and protection functions in this chip. The PWM controller regulates the microprocessor core voltage with a synchronous rectified buck converter. The three linear controllers regulate power for the 1.5V or 3.3V AGP bus power, the 1.5V GTL bus and the 1.8V power for the chip set core voltage and/or cache memory circuits. An integrated 5 bit D/A converter that adjusts the core PWM output voltage from 2.1V to 3.5V in 0.1V increments and from 1.3V to 2.05V in 0.05V increments. The linear controller for AGP bus power is selectable by TTL-compatible SELECT pin status for 1.5V or 3.3V with ±3% accuracy. The other two linear controller provide 1.5V ±3% and 1.8V ±3% or adjustable output voltage by means of external d ivided resistor based on FIX pin status. This chip monitors all the output voltages. Power Good signal is issued when the core voltage is within ±10% of the DAC setting and the other levels are above their under-voltage levels. Over-voltage protection for the core output uses the lower Nchannel MOSFET to prevent output voltage above 116% of the DAC setting. The PWM over-current function monitors the output current by using the voltage drop across the upper MOSFET’s RDS(ON), eliminating the need for a current sensing resistor. Compatible with HIP6021. Provides 4 Regulated Voltages for Microprocessor Core, AGP Bus, Memory and GTL Bus Power. l TTL Compatible 5-bit Digital-to-Analog Core Output Voltage Selection. Range from 1.3V to 3.5V. 0.1V Steps from 2.1V to 3.5V. 0.05V Steps from 1.3V to 2.05V. l ±1.0% Output Voltage for VCORE, ±3.0% Accuracy for Linear Controller Outputs. l Simple Voltage-Mode PWM Control and Built in Internal Compensation Networks. l N-Channel MOSFET Driver for PWM Buck Converter. l Linear Controller Drives Compatible with both N – Chanel MOSFET and NPN Bipolar Series Pass Transistor. l l l l Operates from +3.3V, +5V and +12V Inputs. Fast Transient Response. Full 0% to 100% Duty Ratios. Adjustable Current Limit without External Sense Resistor. l Microprocessor Core Voltage Protection against Upper MOSFET shorted to +5V. l l l Power Good Output Voltage Monitor. Over-Voltage and Over-Current Fault Monitors. 200KHz Free-Running Oscillator Programmable up to 700KHz. n APPLICATIONS l Full Motherboard Power Regulation for Computers. Analog Integrations Corporation 4F, 9, Industry E. 9th Rd, Science Based Industrial Park, Hsinchu Taiwan, ROC DS-1574-00 May 22, 01 TEL: 886-3-5772500 FAX: 886-3-5772510 www.analog.com.tw 1 AIC1574 n TYPICAL APPLICATION +12VIN 10 2.2 µF VCC 28 +3.3VIN L1 VAUX 16 23 OCSET1 UGATE1 PHASE1 VOUT1 L1 + 1 µH GND Q1 +5VIN VOUT2 3.3V or 1.5V Q3 DRIVE2 1 VSEN2 10 27 26 + 25 COUT2 24 SELECT 11 22 LGATE1 Q2 PGND D5820 + COUT1 VSEN1 Q4 VOUT3 1.5V + DRIVE3 18 21 FB VSEN3 19 COUT3 SD 9 20 7 15 6 5 14 4 + COUT4 FIX 2 8 13 17 GND 12 3 NC VID0 VID1 VID2 VID3 VID4 PGOOD FAULT/RT SS Q5 DRIVE4 VOUT4 1.8V VESN4 Css 2 AIC1574 n ORDERING INFORMATION AIC1574-CX PACKAGING TYPE S: SMALL OUTLINE ORDER NUMBER AIC157 4CS (SO2 8) PIN CONFIGURATION DRIVE2 FIX 1 2 28 VCC 27 UGATE1 26 PHASE1 25 LGATE1 24 PGND 23 OCSET 22 VSEN1 21 FB 20 NC 1 9 VSEN3 1 8 DRIVE3 1 7 GND 1 6 VAUX 15 DRIVE4 VID 4 3 VID 3 4 VID 2 5 VID 1 6 VID0 7 PGOOD 8 SD 9 VSEN2 10 SELECT 11 S S 12 FAULT/RT 13 VSEN4 14 n ABSOLUTE MAXIMUM RATINGS Supply Voltage, VCC ...............… … … … … .....… … … … ...… … ...… ..… … ..................... +15V PGOOD, FAULT and GATE Voltage ...… … … … .....… … … ..… .... GND -0.3V to VCC +0.3V Input, Output , or I/O Voltage ......… ...… … … … … … … … ..… … ............ GND -0.3V to 7V Recommended Operating Conditions Supply Voltage; VCC… … ...............… … … … ..................... +12V±10% Ambient temperature Range … … ..… … … … … … ................. 0°C~70°C Junction Temperature Range … … ......… ..… … .................. 0°C~125°C Thermal Information Thermal Resistance, θJA SOIC package … … … … … … … … … … … ..… … ..… … .............. 70°C/W SOIC package (with 3in2 of copper) … ...… … … .........… ......... 50°C/W Maximum Junction Temperature (Plastic Package) Maximum Storage Temperature Range … … … … … … … ..… … ...... 150°C … … … … … … … … … … ..… ... 300°C … … … … … … … … … … … .... -65°C ~ 150°C Maximum Lead Temperature (Soldering 10 sec) n TEST CIRCUIT Refer to APPLICATION CIRCUIT. 3 AIC1574 n ELECTRICAL CHARACTERISTICS PARAMETER VCC SUPPLY CURRENT Supply Current POWER ON RESET Rising VCC Threshold Falling VCC Threshold Rising VAUX Threshold VAUX Threshold Hysteresis Rising VOCSET1 Threshold OSCILLATOR Free Running Frequency Total Variation Ramp. Amplitude REFERENCE AND DAC DAC (VID0~VID4) Input Low Voltage DAC (VID0~VID4) Input High Voltage DACOUT Voltage Accuracy Bandgap Reference Voltage Bandgap Reference Tolerance LINEAR REGULATOR (OUT2, OUT3, OUT4) Regulation VSEN2 Regulation Voltage VSEN2 Regulation Voltage VSEN3 Regulation Voltage VSEN3 Regulation Voltage Under-Voltage Level ( VSEN/VREG) Under-Voltage Hysteresis (V SEN/VREG) Output Drive Current (All Linears ) VSEN Rising VSEN Falling VAUX -V DRIVE > 0.6V Select2.0V VDAC=1.8V~3.5V RT=Open 6k Ω