ISL6420AIRZ-TKR5264

ISL6420A NOT REC OM RECOMM MENDED FOR N EW D ES ENDED R IGNS EPL AC E M ENT PAR ISL6420 T B DATASHEET FN9169 Rev 4.00 December 4, 2009 Advanced Single Synchronous Buck Pulse-Width Modulation (PWM) Controller The ISL6420A simplifies the implementation of a complete control and protection scheme for a high-performance DC/DC buck converter. It is designed to drive N-Channel MOSFETs in a synchronous rectified buck topology. The ISL6420A 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. The ISL6420A 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. 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 ISL6420A 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. Features • Operates From: - 4.5V to 5.5V Input - 5.5V to 28V Input • 0.6V Internal Reference Voltage - ±1.0% Reference Accuracy • Resistor-Selectable Switching Frequency - 100kHz to 1.4MHz • Voltage Margining and External Reference Tracking Modes • Output can Sink or Source Current • Lossless, Programmable Overcurrent Protection - Uses Upper MOSFET’s rDS(ON) • 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 • Diode Emulation during Startup for Pre-Biased Load Applications • Offered in 20 Ld QFN and QSOP Packages • 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 • Pb-Free (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 FN9169 Rev 4.00 December 4, 2009 Page 1 of 21 ISL6420A Ordering Information PART NUMBER (Notes 2, 3) PART MARKING TEMP. RANGE (°C) PACKAGE (Pb-Free) PKG. DWG. # ISL6420AIAZ 6420 AIAZ -40 to +85 20 Ld QSOP M20.15 ISL6420AIAZ-TK (Note 1) 6420 AIAZ -40 to +85 20 Ld QSOP (Tape and Reel) M20.15 ISL6420AIRZ 64 20AIRZ -40 to +85 20 Ld 4x4 QFN L20.4x4 ISL6420AIRZ-TK (Note 1) 64 20AIRZ -40 to +85 20 Ld 4x4 QFN (Tape and Reel) L20.4x4 NOTES: 1. Please refer to TB347 for details on reel specifications. 2. 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. 3. For Moisture Sensitivity Level (MSL), please see device information page for ISL6240A For more information on MSL please see techbrief TB363. Pin Configurations ISL6420A (20 LD QSOP) TOP VIEW BOOT UGATE PHASE PVCC LGATE ISL6420A (20 LD QFN) TOP VIEW PGND 20 19 18 17 16 LGATE 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 FN9169 Rev 4.00 December 4, 2009 20 PGOOD CDEL 1 2 19 ENSS 3 18 COMP 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 Page 2 of 21 VCC5 ENSS 10µA INTERNAL 0.6V VIN INTERNAL SERIES LINEAR REFOUT ENSS ISL6420A FN9169 Rev 4.00 December 4, 2009 Block Diagram POWER-ON OCSET RESET (POR) OTP SSDONE 100µA BOOT GPIO1/REFIN GPIO2 UGATE SSDONE VOLTAGE MARGINING CONTROL FAULT LOGIC SSDONE VMSET/MODE GATE CONTROL LOGIC PHASE CDEL PWM COMP SS VREF FB PVCC EA LGATE COMP PGND OSCILLATOR PGOOD PGOOD COMP OV/UV COMP Page 3 of 21 SGND RT EP (QFN ONLY) ISL6420A Typical 5V Input DC/DC Application Schematic 5V ±10% C6 C1 C3 C2 VIN VCC5 PVCC OCSET MONITOR AND PROTECTION ENSS Q1 PGOOD C8 OSC REF VOUT SGND C11 COMP C12 R5 C10 PGND R6 C13 R4 Q2 LGATE -+ + + - FB R3 L1 PHASE VMSET/MODE CDEL C9 UGATE REFOUT R2 D1 R1 BOOT RT C7 0.1µF C5 C4 GPIO1/REFIN GPIO2 VOLTAGE MARGINING ENABLED WITH INTERNAL VREF SEE PAGE 12 FOR MORE DETAILS Typical 5.5V to 28V Input DC/DC Application Schematic 5.5V to 28V C6 C1 C3 C2 VIN VCC5 PVCC OCSET MONITOR AND PROTECTION ENSS R2 OSC Q1 C9 L1 PHASE CDEL REF C8 VOUT SGND C11 R5 R4 COMP C12 C13 Q2 C10 PGND R6 VMSET/MODE R3 LGATE -+ + + - FB FN9169 Rev 4.00 December 4, 2009 UGATE REFOUT C7 0.1µF D1 R1 BOOT RT PGOOD C5 C4 GPIO1/REFIN GPIO2 VOLTAGE MARGINING ENABLED WITH INTERNAL VREF SEE PAGE 12 FOR MORE DETAILS Page 4 of 21 ISL6420A Typical 5V Input DC/DC Application Schematic 5V ±10% C6 C1 C3 C2 VIN PVCC RT CDEL C7 R2 D1 VCC5 MONITOR AND PROTECTION ENSS C5 C4 OCSET BOOT UGATE OSC R1 Q1 C8 L1 PHASE PGOOD REF 2.5V/1.25V SGND C11 R4 R5 GPIO2 COMP Q2 C9 PGND REFOUT C10 VMSET/MODE R3 LGATE + + - FB GPIO1/REFIN