ISL6527
Single Synchronous Buck Pulse-Width Modulation (PWM) Controller

Key Features

• Operates from 3.3V to 5V Input
• Utilizes an External Reference
• 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
• Lossless, Programmable Overcurrent Protection
• Uses Upper MOSFET's r_DS(ON)
• Converter Can Source and Sink Current
• Small Converter Size
• Internal Fixed Frequency Oscillator
• ISL6527: 300kHz
• ISL6527A: 600kHz
• Internal Soft-Start
• 14 Ld SOIC or 16 Ld 5x5 QFN
• QFN package:
• Compliant to JEDEC PUB95 MO-220 QFN - Quad Flat No Leads - Package Outline
• Near Chip-Scale Package Footprint, which Improves PCB Efficiency and has a Thinner Profile
• Pb-Free (RoHS compliant)

Description

The ISL6527, ISL6527A make simple work out of implementing a complete control and protection scheme for a DC/DC step-down converter. Designed to drive N-Channel MOSFETs in a synchronous buck topology, the ISL6527, ISL6527A integrate the control, output adjustment, monitoring and protection functions into a single package.

The ISL6527, ISL6527A provide simple, single feedback loop, voltage-mode control with fast transient response. The output voltage can be regulated to as low as the provided external reference. A fixed frequency oscillator reduces design complexity, while balancing typical application cost and efficiency.

The error amplifier features a 15MHz gain-bandwidth product and 6V/µs slew rate, which enables high converter bandwidth for fast transient performance. The resulting PWM duty cycles range from 0% to 100%.

Protection from overcurrent conditions is provided by monitoring the r_DS(ON) of the upper MOSFET to inhibit PWM operation appropriately. This approach simplifies the implementation and improves efficiency by eliminating the need for a current sense resistor.

Applications

• Power Supplies for Microprocessors
• PCs
• Embedded Controllers
• Subsystem Power Supplies
• PCI/AGP/GTL+ Busses
• ACPI Power Control
• DDR SDRAM Bus Termination Supply
• Cable Modems, Set-Top Boxes, and DSL Modems
• DSP and Core Communications Processor Supplies
• Memory Supplies
• Personal Computer Peripherals
• Industrial Power Supplies
• 3.3V Input DC/DC Regulators
• Low Voltage Distributed Power Supplies