SS6580/L Step-Down DC/DC Controller with Shutdown n l l l l l l l l l n 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. 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 n specifies the corresponding output voltage for 16 APPLICATIONS l Power Supply for Motherboard VGTL (1.5V Output) l Power Supply for Motherboard VI/O. High-Power 5V to 3.xV DC/DC Regulators. Low-Voltage Distributed Power Supplies. l l 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 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 PIN CONFIGURATION SO-8 TOP VIEW PACKAGING TYPE N: PLASTIC DIP S: SMALL OUTLINE OCSET 1 REFERENCE VOLTAGE 8 VCC SD 2 7 UGATE COMP 3 6 PHASE DEFAULT: 2.00V L: 1.30V FB* 4 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 VOUT L1 5V 1.5µH VIN2 12V R1 10 C1 1µF 1 2 C7 3 33P 90.9K R6 C6 1nF 4 C9 1nF VCC 8 OCSET UGATE COMP PHASE 6 GND FB SS6580 5 C3 1000µF*2 M1 CEB6030L 7 SD + R2 2K2 R9 L2 4K7 7µH D1 SB1020 + C4 1000µF*6 Optional Circuit R7 SW0 VID0 6.04K R8 R5 SW1 VID1 30.1k 3.01K SW2 VID2 15K R3 SW3 VID3 7.5K R4 *C1 must be very close to VCC pin 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 n 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 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 TEST CIRCUIT Refer to TYPICAL APPLICATION CIRCUIT. n ELECTRICAL CHARACTERISTICS (VCC=12V, TA=25°C, unless otherwise specified.) PARAMETER TEST CONDITIONS SYMBOL MIN. TYP. MAX. UNIT VCC Supply Current Nominal Supply UGATE Open IVCC 2 mA 9.5 V Frequency 200 KHz Duty Cycle 88 % Power-On Reset VCC Threshold VOCSET=4.5V Oscillator Internal Reference Voltage Reference Voltage SS6580 SS6580L 1.96 1.27 2.00 1.30 2.04 1.33 V Error Amplifier DC Gain 76 dB GBW 11 MHz SR 6 V/µS Upper Gate Source RUGATE 7 Ω Upper Gate Sink RUGATE 5 Ω IOCSET 200 µA ISS 10 µA Gain-Bandwidth Product Slew Rate Comp=10pF Gate Driver Protection OCSET Current Source SS Current VOCSET =4.5VDC Shutdown Shutdown Low Input VINL Shutdown High Input VINH Shutdown Mode Current Rev.2.01 6/26/2003 0.35 2 V 1 www.SiliconStandard.com V µA 4 of 8 SS6580/L n TYPICAL PERFORMANCE CHARACTERISTICS 100 Vo=3.5V 80 200 Vo=2.0V OCSET (µA) Efficiency (%) 90 70 Vo=1.3V 60 50 198 Tc=134ppm/ C@ 0~100°C 196 194 40 192 30 1 2 3 Fig. 1 4 5 6 IOUT (A) 7 8 9 10 Efficiency vs. Load Current Fig. 3 Over-Current Operation 11 -40 -20 Fig. 2 0 20 40 60 80 100 120 140 160 Temperature (°C) OCSET Current vs. Temperature Fig. 4 Output Clamped by Built-In Soft Start VOUT NOISE Fig. 5 Rev.2.01 6/26/2003 Transient Response www.SiliconStandard.com 5 of 8 SS6580/L n BLOCK DIAGRAM Over Current - PHASE + SD 200µA Power-On Reset Built-In Soft Start + REF Error AMP VCC PWM Comparator + Gate Control UGATE - FB GND COMP n OCSET Oscillator 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 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) 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 Rev.2.01 6/26/2003 - Shutdown pin. Connect this pin to ground for shutdown. 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. PIN 5: GND - Ground pin. 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 - External compensation pin. This pin is connected to the error amplifier output and PWM comparator. An RC network is www.SiliconStandard.com - The chip power supply pin. Recommended supply voltage is 12V. 6 of 8 SS6580/L n APPLICATION CIRCUIT C9 R1 *C1 1µF 1000P R2 C7 33P SD UGATE COMP PHASE 90.9K C6 L1 5V 1.5µF + VCC M1 C3 1000µF*3 R9 L2 4K7 7µF GND FB R6 12V *C1 must be very close to VCC PIN 2.2K OCSET 10 SS6580L D1 SB1020 1000P R7 R5 13K 2K VOUT + 1.5V/10A C4 1000µF*6 *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 MIN MAX A 1.35 1.75 A1 0.10 0.25 B 0.33 0.51 C 0.19 0.25 D 4.80 5.00 E 3.80 4.00 H E e e A A1 C B l 1.27(TYP) H 5.80 6.20 L 0.40 1.27 L 8 LEAD PLASTIC DIP (unit: mm) D E1 E A2 A1 eB e MIN MAX A1 0.381 — A2 2.92 4.96 b 0.35 0.56 C 0.20 0.36 D 9.01 10.16 E 7.62 8.26 E1 6.09 7.12 C L b SYMBOL e 2.54 (TYP) eB — 10.92 L 2.92 3.81 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