ISL6420IRZ-TK

DATASHEET ISL6420 FN9151 Rev 5.00 Feb 13, 2008 Advanced Single Synchronous Buck Pulse-Width Modulation (PWM) Controller The ISL6420 makes simple work out of implementing a complete control and protection scheme for a highperformance DC/DC buck converter. Designed to drive N-channel MOSFETs in a synchronous rectified buck topology, the ISL6420 integrates control, output adjustment, monitoring and protection functions into a single package. Additionally, the IC features an external reference voltage tracking mode for externally referenced buck converter applications and DDR termination supplies, as well as a voltage margining mode for system testing in networking DC/DC converter applications. Features The ISL6420 provides simple, single feedback loop, voltage mode control with fast transient response. The output voltage of the converter can be precisely regulated to as low as 0.6V. • Lossless, Programmable Overcurrent Protection - Uses Upper MOSFET‘s rDS(ON) The operating frequency is fully adjustable from 100kHz to 1.4MHz. High frequency operation offers cost and space savings. The error amplifier features a 15MHz gain-bandwidth product and 6V/µs slew rate that enables high converter bandwidth for fast transient response. The PWM duty cycle ranges from 0% to 100% in transient conditions. Selecting the capacitor value from the ENSS pin to ground sets a fully adjustable PWM soft-start. Pulling the ENSS pin LOW disables the controller. The ISL6420 monitors the output voltage and generates a PGOOD (power good) signal when soft-start sequence is complete and the output is within regulation. A built-in overvoltage protection circuit prevents the output voltage from going above typically 115% of the set point. Protection from overcurrent conditions is provided by monitoring the rDS(ON) of the upper MOSFET to inhibit the PWM operation appropriately. This approach simplifies the implementation and improves efficiency by eliminating the need for a current sensing resistor. • Operates from 4.5V to 16V Input • 0.6V Internal Reference Voltage - ±1.0% Reference Voltage Accuracy • Resistor-Selectable Switching Frequency - 100kHz to 1.4MHz • Voltage Margining and External Reference Tracking Modes • Output Can Sink or Source Current • Programmable Soft-Start • Drives N-Channel MOSFETs • Simple Single-Loop Control Design - Voltage-Mode PWM Control • Fast Transient Response - High-Bandwidth Error Amplifier - Full 0% to 100% Duty Cycle • Extensive Circuit Protection Functions - PGOOD, overvoltage, overcurrent, Shutdown • QFN (4x4) Package - QFN Compliant to JEDEC PUB95 MO-220 QFN - Quad Flat No Leads - Product Outline - QFN Near Chip Scale Package Footprint; Improves PCB Efficiency, Thinner in Profile • Also Available in QSOP Package • Pb-Free Available (RoHS Compliant) Applications • Power Supplies for Microprocessors/ASICs - Embedded Controllers - DSP and Core Processors - DDR SDRAM Bus Termination • Ethernet Routers and Switchers • High-Power DC/DC Regulators • Distributed DC/DC Power Architecture • Personal Computer Peripherals • Externally Referenced Buck Converters FN9151 Rev 5.00 Feb 13, 2008 Page 1 of 20 ISL6420 Pinouts ISL6420 (20 LD QSOP) TOP VIEW 19 PVCC PHASE 18 17 LGATE 20 UGATE BOOT ISL6420 (20 LD QFN) TOP VIEW CDEL 1 PGND 2 19 ENSS 16 LGATE 3 18 COMP GPIO2 1 15 PGND GPIO1/REFIN 2 14 CDEL 12 ENSS VMSET/MODE 5 11 COMP 6 7 8 9 10 FB 4 RT REFOUT SGND 13 PGOOD VIN 3 VCC5 OCSET 20 PGOOD PVCC 4 17 FB PHASE 5 16 RT UGATE 6 15 SGND BOOT 7 14 VIN GPIO2 8 13 VCC5 GPIO1/REFIN 9 12 VMSET/MODE OCSET 10 11 REFOUT Ordering Information PART NUMBER PART MARKING TEMP. RANGE (°C) -40 to +85 PACKAGE 20 Ld 4x4 QFN PKG. DWG. # ISL6420IR ISL 6420IRZ ISL6420IR-T* ISL 6420IRZ ISL6420IRZ (Note) 64 20IRZ ISL6420IRZ-T* (Note) 64 20IRZ 20 Ld 4x4 QFN Tape and Reel (Pb-free) L20.4x4 ISL6420IRZ-TK* (Note) 64 20IRZ 20 Ld 4x4 QFN Tape and Reel (Pb-free) L20.4x4 ISL6420IA ISL 6420IA -40 to +85 ISL6420IA-TK* ISL 6420IA 20 Ld QSOP Tape and Reel ISL6420IAZ (Note) ISL 6420IAZ ISL6420IAZ-TK* (Note) ISL 6420IAZ 20 Ld 4x4 QFN Tape and Reel -40 to +85 -40 to +85 20 Ld 4x4 QFN (Pb-free) 20 Ld QSOP L20.4x4 L20.4x4 L20.4x4 M20.15 M20.15 20 Ld QSOP (Pb-free) 20 Ld QSOP Tape and Reel (Pb-free) M20.15 M20.15 *Please refer to TB347 for details on reel specifications. NOTE: These Intersil Pb-free plastic packaged products employ special Pb-free material sets; molding compounds/die attach materials and 100% matte tin plate PLUS ANNEAL - e3 termination finish, which is 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. FN9151 Rev 5.00 Feb 13, 2008 Page 2 of 20 ISL6420 Functional Block Diagram VIN VCC5 OCSET SGND LDO OVERCURRENT COMP + OCFLT PHASE REFERENCE 0.6V SS + OVFLT UVFLT UGATE FAULT LOGIC PHASE ERROR AMP - FB BOOT + - COMP PHASE LOGIC PWM LOGIC PWM COMP PVCC GPIO1/REFIN LGATE RAMP GENERATOR GPIO2 REFOUT VOLTAGE MARGINING VMSET/MODE OV/UV VOLTAGE MONITOR FB PGND OVFLT UVFLT OSC EN/SS RT ENSS PGOOD CDEL Typical 5V Input DC/DC Application Schematic 5V C6 C1 C3 C2 PVCC VIN VCC5 D1 OCSET MONITOR AND PROTECTION ENSS Q1 PGOOD C8 C9 UGATE OSC R2 CDEL R1 BOOT RT C7 0.1µF C5 C4 L1 PHASE REF 3.3V SGND ++ -- FB R3 C11 COMP Q2 C10 PGND GPIO1/REFIN R6 R5 LGATE -+ + C12 REFOUT GPIO2 C13 R4 FN9151 Rev 5.00 Feb 13, 2008 VMSET/MODE Page 3 of 20 ISL6420 Typical 12V Input DC/DC Application Schematic 12V C6 C1 C3 C2 PVCC VIN VCC5 D1 OCSET MONITOR AND PROTECTION ENSS Q1 PGOOD R2 C9 UGATE OSC L1 PHASE CDEL C8 R1 BOOT RT C7 C5 C4 REF 3.3V SGND R3 C11 C10 PGND COMP GPIO1/REFIN R6 C12 R5 Q2 LGATE -+ + ++ -- FB REFOUT GPIO2 C13 R4 VMSET/MODE Typical 5V Input DC/DC Application Schematic 5V C6 C1 C3 C2 VIN PVCC C4 D1 VCC5 OCSET MONITOR AND PROTECTION SS/EN Q1 CDEL R2 R1 BOOT RT C7 C5 C8 UGATE OSC L1 PHASE PGOOD REF 2.5V/1.25V SGND R3 C10 C11 LGATE -+ + ++ -- FB COMP R5 C9 GPIO1/REFIN