ISL6431 TM Data Sheet June 2001 File Number 9018 Advanced Pulse-Width Modulation (PWM) Features Controller for Home Gateways Operates from +5V Input The ISL6431 is a high efficiency, fixed frequency, 0.8VtoV Output Range IN synchronous buck PWM controller. It is designed for use in - 0.8V Internal Reference applications that convert 5V to lower distributed voltages - 1.5% Over Line Voltage and Temperature required for set-top box, cable modem, DSL modem and residential home gateway core processor, memory and Drives N-Channel MOSFETs peripheral power supplies. Simple Single-Loop Control Design This device makes simple work out of implementing a - Voltage-Mode PWM Control complete control and protection scheme for a DC-DC Fast Transient Response stepdown converter. Designed to drive N-channel MOSFETs Lossless, Programmable Overcurrent Protection in a synchronous buck topology, the ISL6431 integrates the control, output adjustment, monitoring and protection - Uses Upper MOSFETs r DS(ON) functions into a single 8-pin package. Small Converter Size The ISL6431 provides simple, single feedback loop, voltage- - 300kHz Fixed Frequency Oscillator mode control with fast transient response. The output - Internal Soft Start voltage can be precisely regulated to as low as 0.8V, with a - 8 Lead SOIC Package maximum tolerance of 1.5% over temperature and line High Conversion Efficiency voltage variations. A fixed frequency oscillator reduces design complexity, while balancing typical application cost Synchronous/Standard Buck Configuration and efficiency. Applications The error amplifier features a 15MHz gain-bandwidth Cable Modems, Set Top Boxes, and DSL Modems product and 6V/ s slew rate which enables high converter bandwidth for fast transient performance. The resulting DSP and Core Communications Processor Supplies PWM duty cycles range from 0% to 100%. Power Supplies for Microprocessors and Embedded Protection from overcurrent conditions is provided by Controllers monitoring the r of the upper MOSFET to inhibit PWM DS(ON) Memory Supplies operation appropriately. This approach simplifies the Personal Computer Peripherals implementation and improves efficiency by eliminating the need for a current sense resistor. Industrial Power Supplies 5V-Input DC-DC Regulators Ordering Information Low-Voltage Distributed Power Supplies TEMP. RANGE PKG. o PART NUMBER ( C) PACKAGE NO. Pinout ISL6431CB 0 to 70 8 Ld SOIC M8.15 ISL6431IB -40 to 85 8 Ld SOIC M8.15 BOOT 1 8 PHASE UGATE 2 7 COMP/OCSET ISL6431EVAL1 Evaluation Board GND 3 6 FB LGATE 4 5 VCC CAUTION: These devices are sensitive to electrostatic discharge follow proper IC Handling Procedures. 1 1-888-INTERSIL or 321-724-7143 Intersil and Design is a trademark of Intersil Americas Inc. Copyright Intersil Americas Inc. 2001, All Rights ReservedISL6431 Block Diagram VCC POR AND BOOT SAMPLE + SOFTSTART - AND OC UGATE HOLD COMPARATOR PHASE INHIBIT + PWM ERROR COMPARATOR AMP 0.8V GATE + - CONTROL + - LOGIC - PWM VCC FB LGATE COMP/OCSET 20 A OSCILLATOR FIXED 300kHz GND Typical Application V CC C C 3 4 C 5 D BOOT VCC R 1 BOOT 5 1 ISL6431 UGATE COMP/OCSET C 2 6 7 L PHASE OUT 8 R 2 +V =0.8to V O IN C 2 LGATE C 4 7 63 C 1 GND FB R 3 R 4 2