AIC1568 4-bit DAC, Step-Down PWM Power Controller n FEATURE n DESCRIPTION l Compatible with HIP6008. The AIC1568 is a high power, high efficiency l Simple Voltage-Mode PWM Control. switching l Fast Transient Response. performance microprocessor applications. It is l 1.5% 4-Bit Digital-to-Analog Output Voltage. designed to drive an N-channel MOSFET in a l Adjustable Current Limit without External Sense standard buck topology. Featuring a digitally controller optimized for high Resistors. programmable switching regulator, the AIC1568 l Full 0% to 100% Duty Ratio. includes monitoring and protection capabilities in l 200KHz Free-Running Oscillator, Programmable addition up to 350KHz. functions. to all the essential PWM control l Power-Good Output Voltage Monitor. l Short Circuit Protection with Low Short Circuit The internal 4-bit Digital-to-Analog Converter Output Current. (DAC) adjusts the output voltage from 2.0V to TTL Compatible 4-bit Digital-to-Analog Core 3.5V in 0.1V increments. The precision reference Output Voltage Selection, with range from 2.0V to and voltage-mode control can provide output 3.5V in 0.1V increments. regulation within 1.5% over temperature and line l voltage shifts. n APPLICATIONS l The AIC1568 includes an internal 200KHz free- Power Supply for Pentium, Pentium Pro, Power PC and Alpha Microprocessors. l High-Power 5V to 3.xV DC/DC Regulators. l Low-Voltage Distributed Power Supplies. running oscillator that can be adjusted up to 350KHz. The resulting PWM duty ratio ranges from 0% to 100%. The error amplifier features a 11MHz bandwidth and 6V/S slew rate, which enables high converter bandwidth for fast transient response. The AIC1568 provides adjustable over current and short circuit protections. It senses the output current by using the RDS(ON) of the N-channel MOSFET without an external low value sense resistor. It also monitors the output voltage with a window comparator and issues a power good signal when the output is within 10% of the rated output voltage. 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-1568-01 012102 1 AIC1568 n TYPICAL APPLICATION CIRCUIT C9 1000P 10 C2 0.1 F 2.2K C8 0.1F JUMPER VDRI R1 R2 12V C1 1F L1 OCSET VSEN SS RT/OVP VID0 VCC VID1 BOOT VID2 UDRI VID3 PHASE COMP PGOOD GND FB + RFP45N03L M1 at 10A 7H AIC1568 D1 BYV118 33P R6 + C4 1000 F x 6 R4 15K C6 1000P 2.0V VO U T3.5V L2 C7 90.9K VIN 1H 5V C3 1000F x 2 R5 R3 47K 3.01K R7 1.2M C5 0.1F Switching DC/DC Converter n ORDERING INFORMATION AIC1568CXXX PIN CONFIGURATION PACKING TYPE TR: TAPE & REEL TB: TUBE SO-16 TOP VIEW OCSET 1 SS 2 PACKAGING TYPE S: SMALL OUTLINE Example: AIC1568CSTR a in SO-16 Package & Taping & Reel Packing Type 16 VSEN 15 RT/OVP VID0 3 14 VCC VID1 4 VID2 5 13 BOOT 12 UGATE VID3 6 11 PHASE COMP 7 FB 8 10 PGOOD 9 GND 2 AIC1568 n ABSOLUTE MAXIMUM RATINGS Supply Voltage, VCC ....... .................................................. ... ... ... ... ............................. 15V Boot Voltage, VBOOT ... ... ... .......................... .............. ... ... ... ........................................ 15V Input, Output, or I/O Voltage ....................... ... ... ... .... ... ... ......... GND - 0.3V to VCC+0.3V ESD Classification ....................................... ... ................ ... ....... ... ... .................... Class 2 Recommended Operating Conditions Supply Voltage, VCC ....... ...................................................... ... ... ... ... .............. 12V10% Ambient Temperature Range ....... ................... .... ... .............. ... ... ..................... 0C ~ 70C Maximum Operating Junction Temperature............. ......... ............. ... ... ... ................... 100C Thermal Information Thermal Resistance, JA (Typical, Note 1) SOIC Package .................................. ... ... ... ... ... ... ... ... ... ... ... ... ... ........... . 2 SOIC Package (with 3 in of Copper) 100C/W ... ... ... ... ... ... ... ... ... ... ... ... ... ......... .. 90C /W Maximum Junction Temperature (Plastic Package) ... ... ... ... ... ... ..... ... ................... Maximum Storage Temperature Range ... ... ... ... ... ... ... ... ... ............. ......... 150C -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. 3 AIC1568 n ELECTRICAL CHARACTERISTICS (VCC= 12V, TA=25C, unless otherwise specified.) PARAMETER TEST CONDITIONS SYMBOL MIN. TYP. MAX. UNIT VCC Supply Current Nominal Supply UGATE Open IVCC 2 mA Power-On Reset VCC Threshold VOCSET=4.5V 7 Rising VOCSET Threshold 8.5 1.26 V V Oscillator Free Running Frequency RT Open 170 Total Variation 6K<RT<200K -20 Ramp Amplitude RT Open VOSC 200 230 KHz +20 % 1.5 VP-P DAC Output Voltage DAC Output Voltage Accuracy -1.5 +1.5 % Error Amplifier DC Gain 76 dB GBW 11 MHz SR 6 V/S Upper Gate Source RUGATE 8 12 Upper Gate Sink RUGATE 5.5 10 106 115 125 % IOCSET 170 200 230 A IOVP 30 Gain-Bandwidth Product Slew Rate Gate Driver Protection Over-Voltage Trip (V VSEN /VDAC) OCSET Current Source VOCSET =4.5VDC OVP Sourcing Current VVSEN =5.5V, VOVP=0V SS Current ISS SS Sink Current under VVSEN =VDAC, VOCSET=5.0V, Current Limit VPHASE=0V, VFB=VDAC - 50mV SS Sink Current under Hard VVSEN =0, VOCSET =5.0V, Current Limit VPHASE =0V, VFB=0V mA 10 A 130 A 65 mA Power Good Upper Threshold (V VSEN /VDAC) VVSEN rising 106 114 % Lower Threshold (V VSEN /VDAC) VVSEN falling 84 94 % Hysteresis (V VSEN /VDAC) Upper and lower threshold PGOOD Voltage Low IPGOOD=5mA VPGOOD 2 % 0.5 V 4 AIC1568 n BLOCK DIAGRAM 115% + - VSEN 90% VCC OVP 110% 16 14 POWER-ON RESET + POWER GOOD 10 1PGOOD + + - 1A 1 - + 50% OVER CURRENT 2 SS 4V OCSET IOCSET 200A 11 PHASE SOFT SATRT 13 REFERENCE VID0 VID1 VID2 VID3 VDAC 3 4 5 6 FB 8 COMP 7 BOOT 12 4BITS DAC CONTROL LOGIC + + - + - UGATE 9 PWM COMPARATOR ERROR AMP GND 15 RT/OVP OSCILLATOR 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 200 A current source (IOCSET ), and the external MOSFET onresistance (RDS( ON)) jointly set the over current trip point according to the following equation: IPEAK = IOCSET x ROCSET RDS(ON) If FB pin voltage is sensed to be below 50% of the internal voltage reference VDAC, the over current comparator cycles the soft-start function. PIN 2: SS - Soft start pin. Connect a capacitor from this pin to ground. An internal 10A current source provides soft start function for the converter. PIN 3: PIN 4: PIN 5: PIN 6: VID0 VID1 VID2 VID3 - 4-bit DAC voltage select pin. TTL inputs used to set the internal voltage reference VDAC. When left open, these pins are internally pulled up to 5V and provide logic ones. The level of VDAC sets the converter output voltage as well as the PGOOD and OVP thresholds. Table 1 specifies the VDAC voltage for the 16 combinations of DAC inputs. 5 AIC1568 Table 1. Output Voltage Program VID0 VID1 VID2 VID3 VDAC 0 0 0 0 3.5V 1 0 0 0 3.4V 0 1 0 0 3.3V 1 1 0 0 3.2V 0 0 1 0 3.1V 1 0 1 0 3.0V 0 1 1 0 2.9V 1 1 1 0 2.8V 0 0 0 1 2.7V 1 0 0 1 2.6V 0 1 0 1 2.5V 1 1 0 1 2.4V 0 0 1 1 2.3V 1 0 1 1 2.2V 0 1 1 1 2.1V 1 1 1 1 2.0V PIN 11: PHASE - Over current detection pin. Connect the PHASE pin to source of the external MOSFET. This pin detects the voltage drop across the MOSFET RDS(ON) for over-current protection. PIN 12: UGATE- External MOSFET gate drive pin. Connect this pin to gate of the external MOSFET. PIN 13: BOOT - External MOSFET driver power supply pin. To convert 5V main power to VCORE power by driving N-channel MOSFET, supply voltage of no higher than 12V is recommended since the negative power terminal of the internal driver is internally tied to GND. PIN 14: VCC PIN 7: COMP - External compensation pin. This pin is connected to error amplifier output and PWM comparator. An RC network is connected to FB pin to compensate the voltage-control feedback loop of the converter. PIN 8: FB PIN 9: GND - The error amplifier inverting input pin. The FB pin and COMP pin are used to compensate the voltage-control feedback loop. - Signal GND. It also serves as the power GND for the upper gate driver. PIN 10: PGOOD-Power good indicator pin. PGOOD is an open drain output. This pin is pulled low when the converter output is 10% out of the VDAC reference voltage. - The chip power supply pin. Recommended supply voltage is 12V. PIN 15: RT/OVP- Frequency adjustment and overvoltage indicator pin. This pin is multiplexed to provide two functions. The first function is oscillator switching frequency adjustment. Connecting a resistor (RT) from this pin to GND increases the frequency according to the following equation: F S 2 0 0K H z + 5 x 10 5 log RT The second function for this pin is to drive an external SCR in the event of an over voltage fault. PIN 16: VSEN - Converter output voltage sense pin. Connect this pin to the converter output. The PGOOD and OVP comparator circuits use this signal to report output voltage status and perform overvoltage protection function. 6 AIC1568 PHYSICAL DIMENSION l 16 LEAD PLASTIC SO (150 mil) (unit: mm) D H 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 9.80 10.00 E 3.80 4.00 e e A 1.27 (TYP) H 5.80 6.20 L 0.40 1.27 A1 n B C L 7