Renesas Electronics Corporation Single Sync Buck PWM Controller for Broadband Gateway Applications ISL6439IBZ

The ISL6439 makes easy 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 ISL6439 integrates the control, output adjustment, monitoring and protection functions into a single package.brbr The ISL6439 provides simple, single feedback loop, voltagemode control with fast transient response. The output voltage can be precisely regulated to as low as 0.8V, with a maximum tolerance of ±1.5% over temperature and line voltage variations. A fixed frequency oscillator reduces design complexity, while balancing typical application cost and efficiency.brbr 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%.brbr Protection from overcurrent conditions is provided by monitoring the rsubDS(ON)/sub 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.