Synchronous Buck Pulse-Width Modulator (PWM) Controller

® ISL6535 Data Sheet January 17, 2006 FN9255.0 Synchronous Buck Pulse-Width Modulator (PWM) Controller The ISL6535 is a high performance synchronous controller for demanding DC/DC converter applications. It provides overcurrent fault protection and is designed to safely startup into prebiased output loads. The output voltage of the converter can be precisely regulated to as low as 0.597V, with a maximum tolerance of ±1% over the commercial temperature range, and ±1.5% over the industrial temperature range. The ISL6535 provides simple, single feedback loop, voltagemode control with fast transient response. It includes a triangle-wave oscillator that is adjustable from below 50kHz to over 1.5MHz. Full (0% to 100%) PWM duty cycle support is provided. The error amplifier features a 15MHz gain-bandwidth product and 6V/µs slew rate which enables high converter bandwidth for fast transient performance. The ISL6535's overcurrent protection monitors the current by using the rDS(ON) of the upper MOSFET which eliminates the need for a current sensing resistor. Features • Operates from +12V Input • Excellent Output Voltage Regulation - 0.597V Internal Reference - ±1% Over the Commercial Temperature Range - ±1.5% Over the Industrial Temperature Range • Simple Single-Loop Control Design - Voltage-Mode PWM Control • Fast Transient Response - High-Bandwidth Error Amplifier - Full 0% to 100% Duty Ratio - Leading and Falling Edge Modulation • Small Converter Size - Constant Frequency Operation - Oscillator Programmable from 50kHz to Over 1.5MHz • 12V High Speed MOSFET Gate Drivers - 2.0A Source/3A Sink at 12V Low Side Gate Drive - 1.25A Source/2A Sink at 12V High Side Gate Drive - Drives Two N-Channel MOSFETs • Overcurrent Fault Monitor - High-Side MOSFET’s rDS(ON) Sensing - Reduced ~120ns Blanking Time • Converter can Source and Sink Current • Soft-Start Done and an External Reference Pin for Tracking Applications are Available in the QFN Package • Pin Compatible with ISL6522 • Supports Start-Up into Prebiased Loads • Pb-Free Plus Anneal Available (RoHS Compliant) Pinouts ISL6535 (14 LD NARROW SOIC AND 16 LD QFN) TOP VIEW RT 1 OCSET 2 SS 3 COMP 4 FB 5 EN 6 GND 7 14 VCC 13 PVCC 12 LGATE 11 PGND 10 BOOT 9 UGATE 8 PHASE Applications • Power Supply for some Pentium®, PowerPC™, as well as Graphic CPUs • High-Power 12V Input DC/DC Regulators • Low-Voltage Distributed Power Supplies SSDONE OCSET RT VCC Ordering Information 12 PVCC 11 LGATE 10 PGND 9 BOOT 16 SS COMP FB EN 1 2 3 4 5 REFIN 15 14 13 PART NUMBER (Note) ISL6535IBZ ISL6535IRZ PART MARKING 6535IBZ 6535IRZ TEMP. RANGE (°C) 0 to 70 -40 to 85 0 to 70 -40 to 85 PACKAGE (Pb-free) 14 Ld SOIC 14 Ld SOIC PKG. DWG. # M14.15 M14.15 ISL6535CBZ 6535CBZ ISL6535CRZ 6535CRZ 16 Ld 4x4 QFN L16.4x4 16 Ld 4x4 QFN L16.4x4 6 GND 7 PHASE 8 UGATE Add “-T” suffix for tape and reel. NOTE: Intersil Pb-free plus anneal products employ special Pb-free material sets; molding compounds/die attach materials and 100% matte tin plate termination finish, which are RoHS compliant and compatible with both SnPb and Pb-free soldering operations. Intersil Pb-free products are MSL classified at Pb-free peak reflow temperatures that meet or exceed the Pb-free requirements of IPC/JEDEC J STD-020. 1 CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. 1-888-INTERSIL or 1-888-468-3774 | Intersil (and design) is a registered trademark of Intersil Americas Inc. Copyright Intersil Americas Inc. 2006. All Rights Reserved All other trademarks mentioned are the property of their respective owners. Block Diagram EN SS VCC INTERNAL REGULATOR 30µA 6µA REFERENCE VREF = 0.597 V POWER-ON RESET (POR) OCSET 200µA 2 REFIN (QFN ONLY) FB COMP GND FN9255.0 January 17, 2006 BOOT SOFT-START AND FAULT LOGIC SOURCE OCP UGATE ISL6535 EA GATE CONTROL LOGIC PWM PHASE PVCC OSCILLATOR LGATE PGND SSDONE (QFN ONLY) RT ISL6535 Simplified Power System Diagram ROCSET +12V Cvcc Q1 +1.2V to +12VIN LOUT VOUT COUT ISL6535 RFS Q2 CSS R2 R1 Typical Application +12VIN RFILTER CF2 CF1 VCC PVCC BOOT ROCSET SSDONE (QFN ONLY) REFIN (QFN ONLY) OCSET COCSET UGATE PHASE EN LGATE PGND RRT RT Q2 CHFOUT CBOUT Q1 CBOOT LOUT LIN CHFIN DBOOT CBIN VOUT ISL6535 SS CSS COMP C2 C1 R2 FB R1 GND RO C3 R3 3 FN9255.0 January 17, 2006 ISL6535 Absolute Maximum Ratings Supply Voltage, VPVCC,VVCC . . . . . . . . . . . . . . GND - 0.3V to +16V Enable Voltage, VEN . . . . . . . . . . . . . . . . . . . . . GND - 0.3V to +16V Soft-start Done Voltage, VSSDONE . . . . . . . . . . GND - 0.3V to +16V Boot Voltage, VBOOT . . . . . . . . . . . . . . . . . . . . . GND - 0.3V to +36V Phase Voltage, VPHASE . . . . . . . . . VBOOT - 16V to VBOOT + 0.3V All Other Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . GND - 0.3V to 5.0V Thermal Information Thermal Resistance (Typical) θJA (°C/W) θJC (°C/W) SOIC Package (Note 1) . . . . . . . . . . . . 95 N/A QFN Package (Note 2). . . . . . . . . . . . . 47 8.5 Maximum Junction Temperature . . . . . . . . . . . . . . . . . . . . . . 150°C Maximum Storage Temperature Range . . . . . . . . . . . -65°C to 150°C Maximum Lead Temperature (Soldering 10s) . . . . . . . . . . . . 300°C (SOIC - Lead tips only) Operating Conditions Supply Voltage, VVCC . . . . . . . . . . . . . . . . . . . . . . . . . . +12V ±10% Supply Voltage, VPVCC . . . . . . . . . . . . . . . . . . . . . . . . . +12V ±10% Boot to Phase Voltage, VBOOT - VPHASE . . . . . . . . . . . . . .