W83321S/W83321G Winbond N-Channel FET Synchronous Buck Regulator Controller W83321S W83321G -1- Publication Release Date: January, 2006 Revision 0.51 W83321S/W83321G W83321S Data Sheet Revision History PAGES 1 VERSION DATES VERSION 2004/3/19 0.5 N.A 2005/1/21 0.51 N.A ON WEB MAIN CONTENTS All versions before 0.5 are for internal use only. 1. Add Pb-free part no:W83321G 2 5 2. Add separate VCC12 rail for VBOOT application circuit. Please note that all data and specifications are subject to change without notice. All the trademarks of products and companies mentioned in this datasheet belong to their respective owners. LIFE SUPPORT APPLICATIONS These products are not designed for use in life support appliances, devices, or systems where malfunction of these products can reasonably be expected to result in personal injury. Winbond customers using or selling these products for use in such applications do so at their own risk and agree to fully indemnify Winbond for any damages resulting from such improper use or sales. -2- W83321S/W83321G Table of Content1. GENERAL DESCRIPTION ......................................................................................................... 4 2. FEATURES ................................................................................................................................. 4 3. APPLICATIONS .......................................................................................................................... 5 4. PIN-OUT ..................................................................................................................................... 5 5. PIN DESCRIPTION..................................................................................................................... 6 6. INTERNAL BLOCK DIAGRAM ................................................................................................... 7 7. APPLICATION CIRCUIT............................................................................................................. 8 8. LAYOUT PLACEMENT............................................................................................................... 9 9. ELECTRICAL CHARACTERISTICS......................................................................................... 10 10. TYPICAL OPERATING WAVEFORMS .................................................................................... 11 11. PACKAGE DIMENSION OUTLINE........................................................................................... 16 12. ORDERING INSTRUCTION ..................................................................................................... 17 13. HOW TO READ THE TOP MARKING...................................................................................... 17 -3- Publication Release Date: January, 2006 Revision 0.51 W83321S/W83321G 1. GENERAL DESCRIPTION The W83321S is a high-speed, N-Channel synchronous buck regulator controller. The W83321S employs fixed-frequency voltage-mode PWM control architecture. Both high-side and low-side MOSFETs are lower cost N-Channel type. The regulator is biased from a 5V rail and the power for the high-side MOSFET can be supplied by a separate 12V rail or supplied from a local charge pump. Current limit is achieved by monitoring the voltage drop across the on resistance of the low-side MOSFET. This method eliminates the requirement of extra current sensing resistor and avoids false trigger of OC protection when VIN varies. The adaptive non-overlapping MOSFET gate drivers help avoid potential shoot-through problems while maintaining high efficiency. 2. FEATURES y Operates from +5V Input y 0.8V to VIN Output Range - 0.8V Internal Reference - ±1.5% Over Line Voltage and Temperature y Drives N-Channel MOSFETs y Simple Single-Loop Control Design - Voltage-Mode PWM Control y Fast Transient Response y Lossless, Programmable Overcurrent Protection - Uses Lower MOSFET’s Rds (on) - Current limit without sense resistor y Small Converter Size - 250 kHz Fixed Frequency Oscillator - Internal Soft Start - Tiny plastic SOP-8 package -4- W83321S/W83321G 3. APPLICATIONS y Motherboard Power Supplies Regulation y Subsystem Power Supplies - PCI/AGP/GTL+ Buses - ACPI Power Control - SSTL-2 and DDR SDRAM Bus Termination Supply y Cable Modems, Set Top Boxes, and DSL Modems y DSP and Core Communications Processor Supplies y Memory Power Supplies y Personal Computer Peripherals y Industrial Power Supplies y 5V-Input DC-DC Regulators y Low-Voltage Distributed Power Supplies 4. PIN-OUT BOOT 1 8 ISEN UGATE 2 7 COMP GND 3 6 FB LGATE 4 5 VCC W83321 -5- Publication Release Date: January, 2006 Revision 0.51 W83321S/W83321G 5. PIN DESCRIPTION PIN NAME FUNCTION 1 BOOT Supply rail for the high-side MOSFET driver. A bootstrap circuit may be used to create a BOOT voltage or a separate 12V supply can be used. 2 UGATE Gate drive for the high-side N-channel MOSFET. This pin is also monitored by the adaptive shoot through protection circuitry to determine when the high-side MOSFET has turned off. 3 GND 4 LGATE 5 VCC 6 FB Inverting Input of the Error Amplifier. This pin is available for compensation of the control loop. 7 COMP Internal Error Amplifier Output Pin. This pin is available for compensation of the control loop and pulling this pin low with an open drain device will shutdown the IC. 8 ISEN Current limit threshold setting. Connect a resistor (ROCSET) between this pin and the drain of the low-side MOSFET. Ground for analog circuit. Connect it to system ground. Gate drive for the low-side N-channel MOSFET. This pin is also monitored by the adaptive shoot through protection circuitry to determine when the low-side MOSFET has turned off. +5V supply rail for the lower gate driver and control logic circuit. -6- W83321S/W83321G 6. INTERNAL BLOCK DIAGRAM VDD POR 90µA ISEN Soft Start VREF 0.8V Control Ramp Logic BOOT + FB EA - Output UGATE Gate Clamp Control + COMP - Oscillator 250KHz Ramp Generator Logic VDD LGATE 1.5Vp-p GND MOSFET Gate Drivers Power for the high-side driver is through the BOOT pin. This voltage can be supplied by a separate, higher voltage source, or supplied from a local charge pump structure or even the combination of the two. Since the voltage of the low-side MOSFET gate and the high-side MOSFET gate are being monitored to determine the state of the MOSFET, it should be considered carefully to add external components between the gate drivers and their respective MOSFET gates. Doing so may interfere with the shootthrough protection. Current Limit (Over current protection) Current limit is realized by sensing the voltage across the low-side MOSFET while it is on. This method enhances the converter's effeciency and reduces cost by eliminating a current sensing resistor. While low-side MOSFET is turned on, a constant current of 90uA is forced through ROCSET which is an external resistor connected between phase and ISEN, causing a fixed voltage drop. This fixed voltage is compared against VDS and if the latter is higher, the chip enters current limit mode. In the current limit mode both the high-side and low-side MOSFETS are turned off. After a 25ms delay, a soft-start -7- Publication Release Date: January, 2006 Revision 0.51 W83321S/W83321G cycle is initiated. If the cause of the overcurrent is still present after the delay interval, the current limit would be triggered again. The shut dowm - delay - soft start cycle will be repeated indefinitely untill the overcurrent event has cleared. IPEAK = (IOCSET x ROCSET) / RDS(ON) RDS(ON):Low Side MOSFET Resistance 7. APPLICATION CIRCUIT Local charge pump for VBOOT application: R1 3.7K C1 0.1uF VCC5 U1 D1 1 1 L1 C7 2000uF 3 1N4148/Shuttky C8 0.1uF R3 2.2 2 UGATE 3 Q2 3 N DSG ISEN COMP GND 4 LGATE FB VCC 8 C10 6.8nF C4 (OPT) 7 6 5 W83321S 2 C6 2000uF 3.3uH C3 Q1 1uF N DSG 1 2 VOUT=0.8X(R5+R6)/R6 C2 2000uF BOOT C5 2.2nF R4 10 R2 100K VCC5 C9 1uF R5 16K(1%) R6 7.5K(1%) Separate VCC12 rail for VBOOT application: R1 3.7K R7 10 VCC12 C6 2000uF C7 2000uF C8 0.1uF 3.3uH 3 1 2 L1 C3 Q1 1uF N DSG R3 2.2 Q2 N DSG 2 VOUT=0.8X(R5+R6)/R6 C2 2000uF C10 6.8nF C11 1uF U1 1 1 VCC5 C1 1000uF 2 3 3 4 BOOT UGATE ISEN COMP FB GND LGATE VCC 8 6 5 W83321S R5 16K(1%) R6 7.5K(1%) -8- C4 (OPT) 7 C5 2.2nF R4 10 C9 1uF R2 100K VCC5 W83321S/W83321G 8. LAYOUT PLACEMENT G D Q1 C3 1uF S C9 1uF G VCC BOOT L1 D W83321S C2 2000uF Q2 S C6 2000uF C7 2000uF PIN1 C1 0.1uF Layout Notes: 1.Put Q1 and Q2 as close as possible and using wide,short printed circuit traces between Q1 source and Q2 drain. 2.Put C2 and C3 to be near the Q1 drain and Q2 source nodes. 3.Put C1 as close as to BOOT pin. 4.Put C9 as close as to VCC pin. -9- Publication Release Date: January, 2006 Revision 0.51 W83321S/W83321G 9. ELECTRICAL CHARACTERISTICS PARAMETER SYMBOL TEST CONDITIONS MIN TYP MAX UNITS EN=VCC; UGATE and LGATE Open - 3 - mA Rising VDD Threshold - 4.3 4.5 V Falling VDD Threshold - 3.7 - V 200 250 300 kHz ΔVOSC - 1.5 - VP-P VREF -1.5 - 1.5 % - 0.8 - V DC Gain - 85 - dB Gain-Bandwidth - 5.5 - MHz Slew Rate - 4.1 - V/µS VCC SUPPLY CURRENT Nominal Supply ICC POWER-ON RESET OSCILLATOR Free Running Frequency Ramp Amplitude REFERENCE Reference Voltage Tolerance Reference Voltage ERROR AMPLIFIER GATE DRIVERS High-side Gate Source IHGATE-SRC VBOOT=12V,VUGATE=6V 250 - - mA High-side Gate Sink IHGATE-SNK VBOOT=12V,VUGATE=6V 600 - - mA Low-side Gate Source ILGATE-SRC VCC=5V, VLGATE=2.5V 250 - - mA Low-side Gate Sink ILGATE-SNK VCC=5V, VLGATE=2.5V 300 - - mA ISEN 72 90 108 µA VCOMP - 0.4 - V PROTECTION/DISABLE ISEN Current Source Disable Threshold - 10 - W83321S/W83321G 10. TYPICAL OPERATING WAVEFORMS Dead Time: VCC=5V; VOUT=2.5V Channel 1: UGATE Channel 2: LGATE Dead Time: VCC=5V; VOUT=2.5V Channel 1: UGATE Channel 2: LGATE - 11 - Publication Release Date: January, 2006 Revision 0.51 W83321S/W83321G Power On: VCC=5V; VOUT=2.5V Channel 1: VCC Channel 2: VOUT Power Off: VCC=5V; VOUT=2.5V Channel 1: VCC Channel 2: VOUT - 12 - W83321S/W83321G Bootstrap: VCC=5V; VOUT=2.5V Channel 1: UGATE Channel 2: LGATE Channel 3: BOOT Soft Start: VCC=5V; VOUT=2.5V Channel 1: UGATE Channel 2: VOUT - 13 - Publication Release Date: January, 2006 Revision 0.51 W83321S/W83321G Load Transient: VCC=5V; VOUT=2.5V; Cout=2200uF Channel 3: VOUT Channel 4: Iout (Loading=0Æ5A) Load Transient: VCC=5V; VOUT=2.5V; Cout=2200uF Channel 3: VOUT Channel 4: Iout (Loading=5Æ0A) - 14 - W83321S/W83321G Short Hiccup: VCC=5V; VOUT=2.5V; Cout=2200uF with R=0.1(ohm) load. Channel 1: UGATE Channel 2: VOUT Channel4: Iout - 15 - Publication Release Date: January, 2006 Revision 0.51 W83321S/W83321G 11. PACKAGE DIMENSION OUTLINE 8L SOP (150mil) - 16 - W83321S/W83321G 12. ORDERING INSTRUCTION PART NO. PACKAGE REMARKS W83321S 8-pin SOP Operation - Commercial 0~70℃ W83321G 8-pin SOP Operation - Commercial 0~70℃ Pb-free package 13. HOW TO READ THE TOP MARKING W83 321S 323GA W83 321G 323GA Left Line: Winbond Logo 1 st and 2nd Line: the part number,321G is for Pb-free package 3rd Line: Tracking Code 323: packages assembled in Year 03’, week 23 G: assembly house ID; G means GR, O means OSE, etc. A: the IC version - 17 - Publication Release Date: January, 2006 Revision 0.51 W83321S/W83321G Please note that all data and specifications are subject to change without notice. All the trade marks of products and companies mentioned in this data sheet belong to their respective owners. Important Notice Winbond products are not designed, intended, authorized or warranted for use as components in systems or equipment intended for surgical implantation, atomic energy control instruments, airplane or spaceship instruments, transportation instruments, traffic signal instruments, combustion control instruments, or for other applications intended to support or sustain life. Further more, Winbond products are not intended for applications wherein failure of Winbond products could result or lead to a situation wherein personal injury, death or severe property or environmental damage could occur. Winbond customers using or selling these products for use in such applications do so at their own risk and agree to fully indemnify Winbond for any damages resulting from such improper use or sales. - 18 -