SS6580

SS6580/L Step-Down DC/DC Controller with Shutdown n l l l l FEATURES Operating Voltage up to 15V. Simple Voltage-Mode PWM Control. Fast Transient Response. 2V and 1.3V ± 2% Feedback Voltage Reference Options. Adjustable Current Limit without External Sense Resistors. 200 KHz Switching Oscillator. Short-Circuit Protection with Low Short-Circuit Output Current. Low Shutdown Current Built-in Soft Start. n DESCRIPTION The SS6580 is a high-power, high-efficiency voltage-mode switching regulator controller for motherboard VI/O power supply applications. Designed to drive an N-channel MOSFET in a standard buck topology, the SS6580 features a high voltage CMOS output driver with short-circuit protection in an 8-pin package. An external 4-bit Digital-to-Analog Converter (DAC) can be used along with the SS6580 to adjust the output voltage from 2.0V to 3.5V in 0.1V increments. Table 1 on the following page specifies the corresponding output voltage for 16 combinations of DAC inputs as shown in the typical application circuit. The 200 KHz switching frequency allows the use of small external components while maintaining high conversion efficiency. The 11MHz bandwidth and the 6V/µS slew rate of the error amplifier ensure high converter bandwidth and fast transient response. The SS6580 provides both adjustable l l l l l n l l l l APPLICATIONS Power Supply for Motherboard VGTL (1.5V Output) Power Supply for Motherboard VI/O. High-Power 5V to 3.xV DC/DC Regulators. Low-Voltage Distributed Power Supplies. over-current and adjustable short-circuit protection by sensing the output current across the onresistance of the external N-channel MOSFET, rather than an external low value sense resistor. The SS6580L provides a lower reference voltage (1.30V) than the default SS6580 (2.00V) for lower VOUT requirements. Rev.2.01 6/26/2003 www.SiliconStandard.com 1 of 8 SS6580/L n ORDERING INFORMATION SS6580XCXXX PACKING TYPE TR: TAPE & REEL TB: TUBE PACKAGING TYPE N: PLASTIC DIP S: SMALL OUTLINE REFERENCE VOLTAGE DEFAULT: 2.00V L: 1.30V PIN CONFIGURATION SO-8 TOP VIEW OCSET 1 SD 2 COMP 3 FB* 4 8 VCC 7 UGATE 6 PHASE 5 GND *SS6580: 2.00V SS6580L: 1.30V Example: SS6580CSTR à 2.00V in SO-8 Package & Tape & Reel Packing Type (CN is not available in TR packing) n TYPICAL APPLICATION CIRCUIT VIN1 5V 1.5µH VIN2 12V C9 1nF R2 2K2 + C3 1000µF*2 L1 VOUT R1 10 C1 1µF 1 2 OCSET SD COMP FB SS6580 VCC 8 UGATE 7 R9 4K7 D1 SB1020 M1 CEB6030L L2 7µH C4 1000µF*6 + C7 33P 90.9K R6 C6 1nF 3 4 PHASE 6 GND 5 Optional Circuit R7 SW0 VID0 SW1 VID1 SW2 VID2 SW3 VID3 6.04K R8 30.1k R4 15K R3 7.5K *C1 must be very close to VCC pin R5 3.01K Supply DC-DC Step Down Circuit Rev.2.01 6/26/2003 www.SiliconStandard.com 2 of 8 SS6580/L Table 1. Output Voltage Program VID3 VID2 VID1 1 1 1 1 1 1 1 1 0 1 1 0 1 0 1 1 0 1 1 0 0 1 0 0 0 1 1 0 1 1 0 1 0 0 1 0 0 0 1 0 0 1 0 0 0 0 0 0 VID0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 VOUT 2.00V 2.10V 2.20V 2.30V 2.40V 2.50V 2.60V 2.70V 2.80V 2.90V 3.00V 3.10V 3.20V 3.30V 3.40V 3.50V 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 .…................................………….……….................. 0°C~70°C Junction Temperature Range ....…............……….........…..……......................... 0°C~ 100°C Thermal Information Thermal Resistance, θJA (Typical, Note 1) SOIC Package ...............................………………………..……………........…. 100°C/W SOIC Package (with 3 in2 of Copper) ……………………………………......….. 90°C/W Maximum Junction Temperature (Plastic Package) ……….……..………................... 150°C Maximum Storage Temperature Range …………..…………......…….…......... –65°C~150°C Maximum Lead Temperature (Soldering 10 Sec) …………………...……......…......... 300°C Note 1: θJA is measured with the component mounted on an evaluation PC board in free air. Rev.2.01 6/26/2003 www.SiliconStandard.com 3 of 8 SS6580/L n n TEST CIRCUIT Refer to TYPICAL APPLICATION CIRCUIT. ELECTRICAL CHARACTERISTICS specified.) PARAMETER VCC Supply Current Nominal Supply Power-On Reset VCC Threshold Oscillator Frequency Duty Cycle Internal Reference Voltage Reference Voltage Error Amplifier DC Gain Gain-Bandwidth Product Slew Rate Gate Driver Upper Gate Source Upper Gate Sink Protection OCSET Current Source SS Current Shutdown Shutdown Low Input Shutdown High Input Shutdown Mode Current VOCSET =4.5VDC Comp=10pF SS6580 SS6580L VOCSET=4.5V UGATE Open TEST CONDITIONS (VCC=12V, TA=25°C, unless otherwise SYMBOL MIN. TYP. MAX. UNIT IVCC 2 mA 9.5 V 200 88 KHz % 1.96 1.27 2.00 1.30 2.04 1.33 V 76 GBW SR 11 6 dB MHz V/µS RUGATE RUGATE 7 5 Ω Ω IOCSET ISS 200 10 µA µA VINL VINH 2 0.35 V V µA 1 Rev.2.01 6/26/2003 www.SiliconStandard.com 4 of 8 SS6580/L n TYPICAL PERFORMANCE CHARACTERISTICS 100 90 Vo=3.5V Vo=2.0V Vo=1.3V 200 Efficiency (%) 80 70 60 50 40 OCSET (µA) 198 196 Tc=134ppm/ C@ 0~100°C 194 192 30 1 2 3 4 IOUT (A) 5 6 7 8 9 10 11 -40 -20 0 Fig. 1 Efficiency vs. Load Current Fig. 2 Temperature (°C) OCSET Current vs. Temperature 20 40 60 80 100 120 140 160 Fig. 3 Over-Current Operation Fig. 4 Output Clamped by Built-In Soft Start VOUT NOISE Fig. 5 Transient Response Rev.2.01 6/26/2003 www.SiliconStandard.com 5 of 8 SS6580/L n BLOCK DIAGRAM Over Current + PHASE OCSET 200µA SD Built-In Soft Start Power-On Reset VCC + REF FB COMP PWM Comparator + - Gate Control UGATE GND Error AMP Oscillator n PIN DESCRIPTIONS connected to the FB pin to compensate the voltage-control feedback loop of the converter. PIN 4: FB - The error amplifier inverting input pin. The FB pin and COMP pin are used to compensate the voltage-control feedback loop. - Ground pin. PIN 1: OCSET - Current limit sense pin. Connect a resistor ROCSET from this pin to the drain of the external MOSFET. ROCSET, an internal 200µA current source (IOCSET), and the external MOSFET on-resistance (RDS(ON)) jointly set the over-current trip point according to the following equation: IPEAK = IOCSET × ROCSET RDS(ON) PIN 5: GND If the 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: SD PIN 3:COMP - Shutdown pin. Connect this pin to ground for shutdown. - External compensation pin. This pin is connected to the error amplifier output and PWM comparator. An RC network is PIN 6: PHASE - Over-current detection pin. Connect the PHASE pin to the source of the external N-MOSFET. This pin detects the voltage drop across the MOSFET RDS(ON) for over-current protection. PIN 7: UGATE - External MOSFET gate drive pin. Connect this pin to the gate of the external MOSFET. PIN 8: VCC - The chip power supply pin. Recommended supply voltage is 12V. Rev.2.01 6/26/2003 www.SiliconStandard.com 6 of 8 SS6580/L n APPLICATION CIRCUIT C9 1000P R2 2.2K R1 *C1 1µF 10 12V L1 1.5µF + M1 C3 1000µF*3 L2 7µF D1 SB1020 + *C1 must be very close to VCC PIN 5V OCSET SD VCC UGATE PHASE GND C7 R6 90.9K 33P C6 1000P COMP FB R9 4K7 SS6580L VOUT 1.5V/10A C4 1000µF*6 R7 13K R5 2K *VOUT=1.3V(R5+R7)/R7 Fig. 6 DC/DC Step Down Circuit Rev.2.01 6/26/2003 www.SiliconStandard.com 7 of 8 SS6580/L n PHYSICAL DIMENSIONS l 8 LEAD PLASTIC SO (unit: mm) D SYMBOL A A1 H E MIN 1.35 0.10 0.33 0.19 4.80 3.80 5.80 0.40 MAX 1.75 0.25 0.51 0.25 5.00 4.00 6.20 1.27 B C D E e A C A1 e H L L 1.27(TYP) B l 8 LEAD PLASTIC DIP (unit: mm) D SYMBOL A1 E1 MIN 0.381 2.92 0.35 0.20 9.01 7.62 6.09 MAX — 4.96 0.56 0.36 10.16 8.26 7.12 A2 b E C D E C A2 A1 L E1 eB b e e eB L — 2.54 (TYP) 10.92 3.81 2.92 Information furnished by Silicon Standard Corporation is believed to be accurate and reliable. However, Silicon Standard Corporation makes no guarantee or warranty, express or implied, as to the reliability, accuracy, timeliness or completeness of such information and assumes no responsibility for its use, or for infringement of any patent or other intellectual property rights of third parties that may result from its use. Silicon Standard reserves the right to make changes as it deems necessary to any products described herein for any reason, including without limitation enhancement in reliability, functionality or design. No license is granted, whether expressly or by implication, in relation to the use of any products described herein or to the use of any information provided herein, under any patent or other intellectual property rights of Silicon Standard Corporation or any third parties. Rev.2.01 6/26/2003 www.SiliconStandard.com 8 of 8