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AIC1568
4-bit DAC, Simple PWM Power Regulator
FEATURE
Compatible with HIP6008. Simple Voltage-Mode PWM Control. Fast Transient Response. 1.5% 4-Bit Digital-to-Analog Output Voltage. Adjustable Current Limit without External Sense Resistors. Full 0% to 100% Duty Ratio. 200KHz Free-Running Oscillator, Programmable up to 350KHz. Power-Good Output Voltage Monitor. Short Circuit Protection with Low Short Circuit Output Current. The internal 4-bit Digital-to-Analog Converter (DAC) adjusts the output voltage from 2.0V to 3.5V in 0.1V increments. The precision reference and voltage-mode control can provide output regulation within 1.5% over temperature and line voltage shifts. The internal oscillator of the AIC1568 free-runs at 200KHz and 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 across the on resistance 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.
DESCRIPTION
The AIC1568 is a high power, high efficiency switching regulator controller optimized for high performance microprocessor applications. It is designed to drive an N-channel MOSFET in a standard buck topology. Featuring a digitally programmable switching regulator, the AIC1568 includes monitoring and protection capabilities in addition to all the essential PWM control functions.
APPLICATIONS
Power Supply for Pentium, Pentium Pro, Power PC and Alpha Microprocessors. High-Power 5V to 3.xV DC/DC Regulators. Low-Voltage Distributed Power Supplies.
Analog Integrations Corporation DS-1568-00
4F, 9, Industry E. 9th Rd, Science Based Industrial Park, Hsinchu Taiwan, ROC TEL: 886-3-5772500 FAX: 886-3-5772510
www.analog.com.tw
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AIC1568
ORDERING INFORMATION
AIC1568 XX PACKAGE TYPE S: SMALL OUTLINE TEMPERATURE RANGE C: 0C~70C ORDER NUMBER AIC1568CS (PLASTIC SO) PIN CONFIGURATION
TOP VIEW OCSET 1 SS 2 VID0 3 VID1 4 VID2 5 VID3 6 COMP 7 FB 8 16 VSEN 15 RT/OVP 14 VCC 13 BOOT 12 UGATE 11 PHASE 10 PGOOD 9 GND
TYPICAL APPLICATION CIRCUIT
C9 1000P R2 2.2K C8 0.1F VSEN OCSET RT/OVP SS VCC VID0 BOOT VID1 UDRI VID2 PHASE VID3 COMP PGOOD GND FB AIC1568 R4 15K R1 10 C2 0.1F C1 1F
VDRI 12V L1 + VIN
1H 5V C3 1000F x 2 L2 7H 2.0VVOUT3.5V at 10A
JUMPER C7 33P R6 90.9K C6 1000P
RFP45N03L M1
BYV118
D1 + C4 1000F x 6
R5 3.01K R7 1.2M
R3 47K C5 0.1F
Switching Regulator for Pentium VCORE Supply
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AIC1568
ABSOLUTE MAXIMUM RATINGS
Supply Voltage, VCC Boot Voltage, VBOOT .................................................................................................. 15V .................................................................................................. 15V VCC+0.3V Input, Output, or I/O Voltage ................................................... GND - 0.3V to Recommended Operating Conditions Supply Voltage, VCC ....................................................................................... 12V10% 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 in2 of Copper) .................................................. 90C /W 150C 300C Maximum Junction Temperature (Plastic Package) ............................................. Maximum Lead Temperature (Soldering 10 Sec) ...............................................
Note 1: JA is measured with the component mounted on an evaluation PC board in free air.
ESD Classification .............................................................................................. Class 2
Maximum Storage Temperature Range ................................................. -65C ~150C
TEST CIRCUIT
Refer to TYPICAL APPLICATION CIRCUIT.
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AIC1568
ELECTRICAL CHARACTERISTICS
PARAMETER VCC Supply Current Nominal Supply Power-On Reset VCC Threshold Rising VOCSET Threshold Oscillator Free Running Frequency Total Variation Ramp Amplitude DAC Output Voltage DAC Output Voltage Accuracy Error Amplifier DC Gain Gain-Bandwidth Product Slew Rate Gate Driver Upper Gate Source Upper Gate Sink Protection Over-Voltage Trip (VVSEN/VDAC) OCSET Current Source OVP Sourcing Current SS Current SS Sink Current under Current Limit SS Sink Current under Hard Current Limit Power Good Upper Threshold (VVSEN /VDAC) Lower Threshold (VVSEN /VDAC) Hysteresis (VVSEN /VDAC) PGOOD Voltage Low VVSEN rising VVSEN falling Upper and lower threshold IPGOOD=5mA VPGOOD 106 84 2 0.5 114 94 % % % V VVSEN =VDAC, VOCSET=5.0V, VPHASE=0V, VFB=VDAC - 50mV VVSEN=0, VOCSET =5.0V, VPHASE =0V, VFB=0V 65 mA VOCSET =4.5VDC VVSEN =5.5V, VOVP=0V IOCSET IOVP ISS 106 170 30 10 130 115 200 125 230 % A mA A A RUGATE RUGATE 8 5.5 12 10 GBW SR 76 11 6 dB MHz V/S -1.5 +1.5 % RT Open 6KTEST CONDITIONS
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AIC1568
BLOCK DIAGRAM
115% 110% VSEN + =POWER-ON RESET OVP VCC
90% 50% 1A
+ =POWER GOOD + + - +
OVER CURRENT
PGOOD
OCSET
SS 4V
IOCSET 200A
PHASE SOFT SATRT REFERENCE VID0 VID1 VID2 VID3 FB COMP OSCILLATOR RT/OVP VDAC 4BITS DAC + ERROR AMP + + - CONTROL LOGIC PWM COMPARATOR UGATE BOOT
GND
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:
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.
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.
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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
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 - The chip power supply pin. Recommended supply voltage is 12V.
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 - 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 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:
FS 2 0 0 K H z + 5 x 105 lo g RT
PIN 9: GND
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.
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. PIN 11: PHASE - Over current detection pin. Connect
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AIC1568
PHYSICAL DIMENSION
16 LEAD PLASTIC SO (150 mil) (unit: mm)
D
SYMBOL A A1
E H
MIN 1.35 0.10 0.33 0.19 9.80 3.80 5.80 0.40
MAX 1.75 0.25 0.51 0.25 10.00 4.00 6.20 1.27
B C D E e
e A
1.27 (TYP)
H L
A1
B
C
L
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