AIC bit DAC, Synchronous PWM Power Regulator with Linear Controller FEATURES DESCRIPTION APPLICATIONS

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1 5bit DAC, Synchronous PWM Power Regulator with Linear Controller FEATURES Switching Regulator and Low Dropout Linear Regulator on single chip. Simple VoltageMode PWM Control. Dual NChannel MOSFET Synchronous Drive. Fast Transient Response. ±1.0% 5Bit DigitaltoAnalog Output Voltage. Adjustable Current Limit Without External Sense Resistor. Full 0% to 100% Duty Ratio. 200KHz FreeRunning Oscillator Programmable up to 350KHz. PowerGood Output Voltage Monitor. Short Circuit Protection with Low Short Circuit Output Current. TTL Compatible 5bit DigitaltoAnalog core Output Voltage Selection, with range from 1.3V to 3.5V; 0.1V Steps from 2.0V to 3.5V 0.05V Steps from 1.3V to 2.0V APPLICATIONS Power Supply for Pentium II, Power PC and Alpha Microprocessors. HighPower 5V to 3.xV DC/DC Regulators. LowVoltage Distributed Power Supplies. DESCRIPTION The AIC1567 is a high power, high efficiency switching regulator controller optimized for high performance microprocessor applications. It is designed to drive two Nchannel MOSFETs in a standard synchronous buck topology. Featuring a low dropout linear regulator and a digitally programmable switching regulator, the AIC1567 includes monitoring and protection capabilities in addition to all the essential synchronous PWM control functions. The internal 5bit DigitaltoAnalog Converter (DAC) adjusts the output voltage from 2.0V to 3.5V in 0.1V increments and 1.3V to 2.0V in 0.05V increments. The precision reference and voltagemode control can provide output regulation within ±1.0% over temperature and line voltage shifts. The AIC1567 includes an internal 200KHz freerunning 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/µS slew rate, which enables high converter bandwidth for fast transient response. Analog Integrations Corporation 4F, 9 Industry E. 9th Rd, ScienceBased Industrial Park, Hsinchu, Taiwan DS TEL: FAX:

2 TYPICAL APPLICATION CIRCUIT R6 90.9K 0.1µF C7 C8 33pF VID4 C6 1000pF 1000pF R2 2.2K VSEN SS RT LGATE PGND BOOT UGATE VID4 PHASE COMP PGOOD FB GND CLP LIDRI AIC1567 R % R5 3.01KΩ 10 C2 0.1µ F M3 FD3055 R % R9 C1 1µF 5V V I/O 3.3V 10A C1 R8 1.2M 1000µ F 12V R 15K NDP603AL R3 47K C5 M2 0.1µ F M1 D1 RFP45N03L 1N5820 C3 1000µF x 3 L2 L1 1µH 5V 3µ H C4 1000µF x 8 V CORE Switching DC/DC Converter ORDERING INFORMATION AIC1567CXXX PIN CONFIGURATION PACKING TYPE TR: TAPE & REEL TB: TUBE PACKAGING TYPE S: SMALL OUTLINE SO24 TOP VIEW VSEN SS RT LGATE PGND BOOT Example: AIC1567CSTR in SO24 Package & Taping & Reel Packing Type VID4 COMP FB CLP CLN UGATE PHASE PGOOD GND LIDRI VLFB 2

3 ABSOLUTE MAXIMUM RATINGS Supply Voltage, V CC V Boot Voltage, V BOOT V Input, Output, or I/O Voltage GND 0.3V to 0.3V ESD Classification Class 2 Recommended Operating Conditions Supply Voltage, V CC V±10% Ambient Temperature Range C ~ 70 C Maximum Operating Junction Temperature C Thermal Information Thermal Resistance, θ JA (Typical, Note 1) SOIC Package C/W SOIC Package (with 3 in 2 of Copper) C/W Maximum Junction Temperature (Plastic Package) C Maximum Storage Temperature Range C~150 C Maximum Lead Temperature (Soldering 10 sec) C Note 1: symbol θ JA is measured with the component mounted on an evaluation PC board in free air. TEST CIRCUIT Refer to TYPICAL APPLICATION CIRCUIT. ELECTRICAL CHARACTERISTICS (= 12V, T A =25 C, unless otherwise specified.) PARAMETER TEST CONDITIONS SYMBOL MIN. TYP. MAX. UNIT Supply Current Nominal Supply UGATE Open I 2 ma PowerOn Reset V CC Threshold V =4.5V V Rising V Threshold 1.26 V Oscillator Free Running Frequency R T Open KHz Total Variation 6KΩ< R T <200KΩ % Ramp Amplitude R T Open V OSC 1.5 V PP 3

4 ELECTRICAL CHARACTERISTICS (Continued) PARAMETER TEST CONDITIONS SYMBOL MIN. TYP. MAX. UNIT Reference and DAC DACOUT Voltage Accuracy V DAC =1.8V ~3.5V % Error Amplifier DC Gain 76 db GainBandwidth Product GBW 11 MHz Slew Rate SR 6 V/µS Gate Driver Upper Gate Source R UGATE Ω Upper Gate Sink R UGATE Ω Lower Gate Source R LGATE Ω Lower Gate Sink R LGATE Ω Protection OverVoltage Trip (V SEN/DACOUT ) % Current Source V =4.5VDC I µa Sourcing Current V VSEN =5.5V, V =0V I 30 ma Soft Start Current I SS 10 µa Soft Start Sink Current under V VSEN =V DAC, V =5.0V, 130 µa Current Limit V PHASE =0V, V FB =VDAC=50mV Soft Start Sink Current under V VSEN =0, V =5.0V, 65 ma Hard Current Limit V PHASE =0V, V FB =0V Power Good Upper Threshold (V VSEN /V DAC ) V VSEN Rising % Lower Threshold (V VSEN / V DAC ) V VSEN Falling % Hysteresis (V VSEN / V DAC ) Upper and Lower Threshold 2 % PGOOD Voltage Low I PGOOD =5mA V PGOOD 0.5 V Linear Regulator VLFB Feedback Voltage V VLFB Bias Current 40 na LIDRI Sourcing Current 10 ma Current Limiting Threshold mv 4

5 5 BLOCK DIAGRAM PWM COMPARATOR CURRENT SENSE LINEAR AMP. ERROR AMP CLN VDAC 1.2V CLP COMP FB VLFB LIDRI OSCILLATOR REFERENCE 5BITS DAC RT PHASE OVER CURRENT VSEN SOFT START 200µA CONTROL LOGIC POWERON RESET 50% POWER GOOD 90% PGOOD 110% 115% GND BOOT UGATE 10µA 4V SS 20mV VID4 PGND LGATE

6 PIN DESCRIPTIONS PIN 1: VSEN PIN 2: Converter output voltage sense pin. Connect this pin to the converter output. The PGOOD and comparator circuits use this signal to report output voltage status and for overvoltage protection function. Current limit sense pin. Connect a resistor R from this pin to the drain of the external MOSFET. R, an internal 200µA current source (I OCS ), and the external MOSFET onresistance (R DS(ON) ) jointly set the over current trip point according to the following equation: I PEAK I = OCS R R DS ( ON) If FB pin voltage is sensed to be below 50% of the internal voltage reference VDAC, the over current comparator cycles the softstart function. PIN 3: SS Soft start pin. Connect a capacitor from this pin to ground. An internal 10µA current source provides soft start function for the converter. PIN 4: PIN 5: PIN 6: PIN 7: PIN 8: VID4 PIN 9: COMP 5bit 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 thresholds. Table 1 specifies the VDAC voltage for the 32 combinations of DAC inputs. 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 voltagecontrol feedback loop of the converter. PIN 10: FB The error amplifier inverting input pin. The FB pin and COMP pin are used to compensate the voltagecontrol feedback loop. PIN 11: CLP PIN 12: CLN PIN 13: VLFB PIN 14: LIDRI PIN 15: GND Linear regulator current sense pin. This pin is the positive input of the current sense comparator. Linear regulator current sense pin. This pin is the negative input of the current sense comparator. Negative feedback pin for the linear regulator error amplifier. Linear regulator output drive pin. This pin can drive either a Darlington NPN or an Nchannel MOSFET. Signal GND. It also serves as the power GND for the upper gate driver. PIN 16: 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. Table 1. Output Voltage Program VID4 VDAC V V V V V V V V V V V V V V 6

7 V V V V V V V V V V V V V V V V V V PIN 17: PHASE Over current detection pin. Connect the PHASE pin to source of the external MOSFET. This pin detects the voltage drop across the MOSFET R DS(ON) for overcurrent protection. PIN 18: UGATE External MOSFET gate drive pin. Connect UGATE to gate of the external MOSFET. PIN 19: BOOT External MOSFET driver power supply pin. To convert 5V main power to V CORE power by driving Nchannel 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 20: PGND Driver power GND pin. PGND should be connected to a low impedance ground plane in close to lower N MOSFET source. PIN 21: LGATE Lower NMOSFET gate driver pin. PIN 22: The chip power supply pin. It also serves as power supply for LGATE driver. Recommended supply voltage is 12V. PIN 23: Over voltage indicator pin. This pin also provides a driver source current to turn on an external SCR in the event of an over voltage condition. PIN 24: RT Frequency adjustment pin. Connecting a resistor (RT) from this pin to GND, increase the frequency by the following equation. F S KHz log RT PHYSICAL DIMENSIONS 24 LEAD PLASTIC SO (300 mil) (unit: mm) D SYMBOL MIN MAX A A E H B C D e A E e 1.27(TYP) H B A1 C L L