ISL6426
Single Synchronous Buck Pulse-Width Modulation (PWM) Controller

Key Features

• Operates from 3.3V/5V Input
• 0.8V to V_IN Output Range
• 0.8V Internal Reference
• ±1.5% Reference Accuracy
• Simple Single-Loop Control Design
• Voltage-Mode PWM Control
• Fast Transient Response
• High-Bandwidth Error Amplifier
• Lossless, Programmable Overcurrent Protection
• Uses Upper MOSFET's r_DS(ON)
• Programmable Switching Frequency 100kHz-700kHz
• External Frequency Synchronization
• Two Device Options Available
• ISL6406 Adjustable Output Voltage
• ISL6426 Fixed 1.8V Output
• Internal Soft-Start
• QFN Package Option
• 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 Packaging Available (RoHS Compliant)
• Designated with "Z" Suffix (Refer to Note)

Description

The ISL6406, ISL6426 is an adjustable frequency, synchronous buck switching regulator optimized for generating lower voltages for the distributed DC-DC architectures. The ISL6406 offers an adjustable output voltage, while the ISL6426 provides a fixed 1.8V output.

Designed to drive N-Channel MOSFETs in synchronous buck topology, the ISL6406, ISL6426 integrates the control, output adjustment and protection functions into a single package.

The ISL6406, ISL6426 provides simple, single feedback loop, voltage-mode control with fast transient response. The output voltage can be precisely regulated to as low as 0.8V. The error amplifier features a 15MHz gain-bandwidth product and 6V/µs slew rate which enables high converter bandwidth for fast transient performance.

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.

The wide programmable switching frequency range of 100kHz to 700kHz allows the use of small surface mount inductors and capacitors. The device also provides external frequency synchronization making it an ideal choice for DC-DC converter applications.

Applications

• 3V/5V DC-DC Converter Modules
• Distributed DC-DC 3.3V, 2.5V and 1.8V Power Architectures for DSP, Logic, and Memory
• Power Supplies for Microprocessors
• PCs
• Embedded Controllers
• Memory Supplies
• Personal Computer Peripherals